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Comparison of the BackJoy SitSmart Relief and Spine Buddy LT1 H/C Ergonomic Chair Supports on Short-Term Neck and Back Pain

Published:December 02, 2016DOI:https://doi.org/10.1016/j.jmpt.2016.10.006

      Abstract

      Objective

      The purpose of this study was to perform a needs assessment to determine whether short-term use of BackJoy SitSmart Relief and Spine Buddy LT1 H/C chair supports influences neck, upper back, and lower back pain.

      Methods

      Forty-eight college students (age, 27.5 ± 6.3 years; height, 1.72 ± 0.08 m; body mass, 78.7 ± 19.8 kg; time seated that day, 4.3 ± 2.8 hours; means ± SD) were recruited for this study. The Nordic Musculoskeletal Questionnaire was used to measure pain for the neck, upper back, and lower back regions. Subjects were randomized to sit in a stationary office chair for a single 12-minute period under 1 of 4 conditions: office chair only (control group), BackJoy SitSmart Relief and chair, freezer-cooled Spine Buddy LT1 H/C and chair, or microwave-heated Spine Buddy LT1 H/C and chair. Participants then completed a posttest Nordic Musculoskeletal Questionnaire. A between-within repeated-measures analysis of variance using the between-subject factor intervention (group) and within-subject factor time (baseline and posttest) was used to analyze study data.

      Results

      The main effect of time across the whole sample was statistically significant for neck (P = .000), upper back (P = .032), and lower back (P = .000) pain; however, there was no statistically significant interaction effect between intervention and time. Thus, as long as participants sat down and rested, symptoms improved similarly across the different groups.

      Conclusions

      In this preliminary study, short-term and single use of a support product for an office chair had no additive effect on reducing neck and back pain.

      Key Indexing Terms

      Introduction

      Neck pain and back pain are both associated with significant economic
      • Lin C.
      • Haas M.
      • Maher C.
      • Machado L.
      • van Tulder M.
      Cost-effectiveness of guideline-endorsed treatments for low back pain: a systematic review.
      • Dagenais S.
      • Caro J.
      • Haldeman S.
      A systematic review of low back pain cost of illness studies in the United States and internationally.
      • Lerner D.
      • Rogers W.
      • Chang H.
      • et al.
      The health care and productivity costs of back and neck pain in a multi-employer sample of utility industry employees.
      • Serrano-Aguilar P.
      • Kovacs F.
      • Cabrera-Hernández J.
      • Ramos-Goñi J.
      • García-Pérez L.
      Available costs of physical treatments for chronic back, neck, and shoulder pain within the Spanish National Health Service: a cross-sectional study.
      and quality-of-life costs.
      • Tüzün E.
      Quality of life in chronic musculoskeletal pain.
      • Linton S.
      A review of psychosocial risk factors in back and neck pain.
      • Scholich S.
      • Hallner D.
      • Wittenberg R.
      • Hasenbring M.
      • Rusu A.
      The relationship between pain, disability, quality of life and cognitive behavioral factors in chronic back pain.
      Neck pain is estimated to affect 30% to 50% of adults annually,
      • Carroll L.
      • Hogg-Johnson S.
      • van der Velde G.
      • et al.
      Course and prognostic factors for neck pain in the general population: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders.
      and the lifetime prevalence rate of back pain is projected to be 39%.
      • Hoy D.
      • Bain C.
      • Williams G.
      • et al.
      A systematic review of the global prevalence of low back pain.
      • Beaudet N.
      • Courteau J.
      • Sarret P.
      • Vanasse A.
      Prevalence of claims-based recurrent low back pain in a Canadian population: a secondary analysis of an administrative database.
      Both conditions are associated with significant medical costs, with back pain treatment accounting for the majority of the costs.
      • Ricci J.
      • Stewart W.
      • Chee E.
      • Leotta C.
      • Foley K.
      • Hochberg M.
      Back pain exacerbations and lost productive time costs in United States workers.
      • Furlan A.
      • Yazdi F.
      • Tsertsvadze A.
      • et al.
      A systematic review and meta-analysis of efficacy, cost-effectiveness, and safety of selected complementary and alternative medicine for neck and low-back pain.
      Studies have suggested that back pain costs the United States 7 to 20 billion US dollars per year, with most of this expense for chronic back pain.
      • Ricci J.
      • Stewart W.
      • Chee E.
      • Leotta C.
      • Foley K.
      • Hochberg M.
      Back pain exacerbations and lost productive time costs in United States workers.
      • Furlan A.
      • Yazdi F.
      • Tsertsvadze A.
      • et al.
      A systematic review and meta-analysis of efficacy, cost-effectiveness, and safety of selected complementary and alternative medicine for neck and low-back pain.
      When employees are not feeling well because of significant neck or back pain, increases in office absenteeism
      • Furlan A.
      • Yazdi F.
      • Tsertsvadze A.
      • et al.
      A systematic review and meta-analysis of efficacy, cost-effectiveness, and safety of selected complementary and alternative medicine for neck and low-back pain.
      • Murtezani A.
      • Hundozi H.
      • Orovcanec N.
      • Berisha M.
      • Meka V.
      Low back pain predict sickness absence among power plant workers.
      • Hoogendoorn W.
      • Bongers P.
      • de Vet H.
      • Ariëns G.
      • van Mechelen W.
      • Bouter L.
      High physical work load and low job satisfaction increase the risk of sickness absence due to low back pain: results of a prospective cohort study.
      • Infante-Rivard C.
      • Lortie M.
      Relapse and short sickness absence for back pain in the six months after return to work.
      • Punnett B.
      • Greenidge D.
      • Ramsey J.
      Job attitudes and absenteeism: a study in the English speaking Caribbean.
      and presenteeism
      • Aronsson G.
      • Gustafsson K.
      • Dallner M.
      Sick but yet at work: an empirical study of sickness presenteeism.
      • Johns G.
      Presenteeism in the workplace: a review and research agenda.
      • Bostrom M.
      • Dellve L.
      • Thomee S.
      • Hagberg M.
      Risk factors for generally reduced productivity: a prospective cohort study of young adults with neck or upper-extremity musculoskeletal symptoms.
      • Hagberg M.
      • Vilhelmsson R.
      • Tornqvist E.
      • Toomingas A.
      Incidence of self-reported reduced productivity owing to musculoskeletal symptoms: association with workplace and individual factors among computer users.
      rates can be seen. Office absenteeism is when an employee misses work because of illness or incapacity.
      • Punnett B.
      • Greenidge D.
      • Ramsey J.
      Job attitudes and absenteeism: a study in the English speaking Caribbean.
      Office presenteeism is when an injured employee attends work, but exhibits reduced work productivity because of an injury.
      • Johns G.
      Presenteeism in the workplace: a review and research agenda.
      Both of these conditions can negatively affect a company in terms of productivity and medical care expenditures. Measures to help workers cope more effectively with neck or back pain may be able to lessen these concerns.
      Two chair support products marketed to reduce symptoms of neck and back pain are the BackJoy SitSmart Relief product and the Spine Buddy LT1 H/C pad.

      BackJoy: SitSmart Relief [Internet]. Boulder, CO: BackJoy; c2010-2015. Available at http://www.backjoy.com/sit-products/. Accessed March 1, 2015.

      Spine Buddy: Spine Buddy LT1 H/C memory foam chair support [Internet]. Humble, TX: Spine Buddy; c2014-2015. Available at http://www.myspinebuddy.com. Accessed February 1, 2015.

      BackJoy product advertisements claim that it “Works for all types of conditions [to include] lower back, neck, tailbone, and upper back” pain, and that 87% of product users report less pain.

      BackJoy: SitSmart Relief [Internet]. Boulder, CO: BackJoy; c2010-2015. Available at http://www.backjoy.com/sit-products/. Accessed March 1, 2015.

      Computer-generated illustrations on their website and their accompanying text claim that their product improves posture through restoration of the lumbar lordotic curve while sitting, which diminishes spine-related pain. Their website does not provide any evidence that their product has ever been scientifically tested to substantiate that it alters the spinal curve while seated. Additionally, a search of the databases Index to Chiropractic Literature, PubMed, Alt Health Watch, and Cumulative Index to Nursing and Allied Health Literature (CINAHL), using the key words “BackJoy” and “SitSmart Relief” did not reveal any research specifically on their product. Despite this, there does exist evidence that seated lumbar kyphosis can lead to lower back pain.
      • Pynt J.
      • Mackey M.
      • Higgs J.
      Kyphosed seated postures: extending concepts of postural health beyond the office.
      • Harrison D.
      • Harrison S.
      • Croft A.
      • Harrison D.
      • Troyanovich S.
      Sitting biomechanics: Part I: Review of literature.
      • Lord M.
      • Small J.
      • Dinsay J.
      • Watkins R.
      Lumbar lordosis: effects of sitting and standing.
      • Andersson G.
      • Murphy R.
      • Ortengren R.
      • Nachemson A.
      The influence of backrest inclination and lumbar support on lumbar lordosis.
      • Andersson B.
      • Örtengren R.
      Lumbar disc pressure and myoelectric back muscle activity during sitting: II. Studies on an office chair.
      • Keegan J.
      Alterations of the lumbar curve related to posture and seating.
      The Spine Buddy company is a newer company in the support pad market compared with the more established BackJoy company.

      BackJoy: SitSmart Relief [Internet]. Boulder, CO: BackJoy; c2010-2015. Available at http://www.backjoy.com/sit-products/. Accessed March 1, 2015.

      Spine Buddy: Spine Buddy LT1 H/C memory foam chair support [Internet]. Humble, TX: Spine Buddy; c2014-2015. Available at http://www.myspinebuddy.com. Accessed February 1, 2015.

      Although the Spine Buddy company has engaged in research on some of their products,
      • Ward J.
      • Coats J.
      • Pourmoghaddam A.
      Spine buddy® supportive pad impact on single-leg static balance and jogging gait of individuals wearing a military backpack.
      • Ward J.
      • Coats J.
      Anterior-to-posterior protective capabilities of the Spine Buddy® jockey vest support pad.
      • Ward J.
      • Coats J.
      • Devers A.
      • Murphy B.
      Supportive pad impact on upper extremity blood flow while wearing a military backpack.
      a similar search on their website and online health care journal databases revealed that the Spine Buddy LT1 H/C has not been tested either. Their product is marketed to relieve neck and lower back pain of seated individuals, as is the BackJoy SitSmart Relief. The Spine Buddy LT1 H/C (H for hot and C for cold) chair support is unique in that it is made of a composite material that can be cooled or heated in an attempt to provide pain relief. Cooling
      • Selkow N.
      • Day C.
      • Liu Z.
      • Hart J.
      • Hertel J.
      • Saliba S.
      Microvascular perfusion and intramuscular temperature of the calf during cooling.
      • Mila-Kierzenkowska C.
      • Jurecka A.
      • Woźniak A.
      • Szpinda M.
      • Augustyńska B.
      • Woźniak B.
      The effect of submaximal exercise preceded by single whole-body cryotherapy on the markers of oxidative stress and inflammation in blood of volleyball players.
      • de Jong R.
      • Hershey W.
      • Wagman I.
      Nerve conduction velocity during hypothermia in man.
      • Eldred E.
      • Lindsley D.
      • Buchwald J.
      The effect of cooling on mammalian muscle spindles.
      • Lippold O.
      • Nicholls J.
      • Redfearn J.
      A study of the afferent discharge produced by cooling a mammalian muscle spindle.
      • Prentice W.
      Therapeutic Modalities in Rehabilitation.
      and heating
      • Mense S.
      Effects of temperature on the discharges of muscle spindles and tendon organs.
      • DeVries H.
      Quantitative electromyographic investigation of the spasms theory of muscle pain.
      • Mendell L.
      Constructing and deconstructing the gate theory of pain.
      of soft tissues is a well-established form of care to decrease pain through several different mechanisms. Cryotherapy can induce vasoconstriction to decrease swelling,
      • Selkow N.
      • Day C.
      • Liu Z.
      • Hart J.
      • Hertel J.
      • Saliba S.
      Microvascular perfusion and intramuscular temperature of the calf during cooling.
      lower localized proinflammatory cytokines (histamine, kinins, and prostaglandins),
      • Mila-Kierzenkowska C.
      • Jurecka A.
      • Woźniak A.
      • Szpinda M.
      • Augustyńska B.
      • Woźniak B.
      The effect of submaximal exercise preceded by single whole-body cryotherapy on the markers of oxidative stress and inflammation in blood of volleyball players.
      decrease sensory nerve conduction,
      • de Jong R.
      • Hershey W.
      • Wagman I.
      Nerve conduction velocity during hypothermia in man.
      diminish spasms,
      • Eldred E.
      • Lindsley D.
      • Buchwald J.
      The effect of cooling on mammalian muscle spindles.
      • Lippold O.
      • Nicholls J.
      • Redfearn J.
      A study of the afferent discharge produced by cooling a mammalian muscle spindle.
      and lower pain perception through the gate theory of pain control.
      • Prentice W.
      Therapeutic Modalities in Rehabilitation.
      Thermotherapy, similarly, has been found to reduce spasms
      • Mense S.
      Effects of temperature on the discharges of muscle spindles and tendon organs.
      • DeVries H.
      Quantitative electromyographic investigation of the spasms theory of muscle pain.
      and to decrease pain perception through use of the gate theory of pain control.
      • Mendell L.
      Constructing and deconstructing the gate theory of pain.
      The purpose of this study was to compare the relative efficacy of 2 chair support pads in reducing neck and back pain in seated individuals after a single session. Neither product has been adequately tested to validate the claims by their respective companies. Consumers should be aware if the products they are purchasing are not meeting their claims so that they may purchase alternative, more impactful products.

      Methods

      This study was reviewed and approved by the Texas Chiropractic College institutional review board for human subjects in accordance with the Declaration of Helsinki. This trial was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) under Trial No. UMIN 000017275 (Regist. No. R000020048).

      Study Design, Rationale, and Setting

      This study focused on the immediate effect of 2 different ergonomic chair support products on self-reported neck and back pain (Fig 1, Fig 2).
      Figure thumbnail gr1
      Fig 1Image of the 4 study groups: A, chair only; B, BackJoy SitSmart Relief product; C, freezer-cooled Spine Buddy LT1 H/C; D, microwave-heated Spine Buddy LT1 H/C. Masking tape was used to mark the specific location on the floor for the chair wheels to ensure similar placement for all participants.
      Figure thumbnail gr2
      Fig 2Close-up images of the (A) BackJoy SitSmart Relief and (B) Spine Buddy LT1 H/C products and (C) removable composite memory foam cushion from the Spine Buddy.

      Participant Recruitment

      Study enrollment took place from February to April 2014 among college students. This specific population was chosen because students often sit for long periods
      • Deliens T.
      • Deforche B.
      • Bourdeaudhuij I.
      • Clarys P.
      Determinants of physical activity and sedentary behavior in university students: a qualitative study using focus group discussions.
      and thus represent a demographic pertinent to this research. Two faculty members announced the research project to students in their classes. Study applicants contacted the primary investigator for screening to determine whether they met the inclusion and exclusion criteria (Table 1).
      Table 1Study Inclusion and Exclusion Criteria
      Inclusion CriteriaExclusion Criteria
      College student aged 18-65 yDiagnosis of blood vessel or neurologic disorder that would result in decreased ability to perceive pain
      Provision of informed written consentWearing sweaty or damp clothing
      Height between 5 ft, 5 in and 5 ft, 10 in for the Spine Buddy groupWearing a sports bra or similar minimalist clothing that would place most of their back directly in contact with the cooled or heated Spine Buddy product
      Weight >100 lb for the BackJoy group
      All study applicants provided written informed consent prior to participating in this study. Table 2 lists the attributes of study participants. This study used a convenience sample of 58 study applicants and did not follow an a priori power analysis. Study applicants were randomized to the 4 study groups based on a pregenerated computer randomization list. Ten applicants assigned to the 2 Spine Buddy groups based on randomization were excluded from this study because of failure to meet the study inclusion criteria. All 10 of those applicants were outside of the 5 ft, 5 in to 5 ft, 10 in height range recommended by the manufacturer for the product. The manufacturers of the BackJoy SitSmart Relief do not provide a recommended height range, but do suggest that users of the adult-sized product should weigh ≥100 lb. All participants in that group were >100 lb. If study applicants met the inclusion criteria and fully participated in the study, they were referred to as study participants for discussion purposes.
      Table 2Participant Demographics and Anthropometric Attributes
      Chair-Only Control GroupBackJoy GroupCold Spine Buddy GroupHeated Spine Buddy GroupP Value
      Sex (M/F)6/88/63/74/6
      Age (y)
      Mean ± SD.
      28.0 ± 6.927.4 ± 5.128.4 ± 9.126.2 ± 5.4.875
      Mass (kg)
      Mean ± SD.
      84.0 ± 24.577.1 ± 17.177.2 ± 20.675.2 ± 16.7.705
      Height (m)
      Mean ± SD.
      1.71 ± 0.111.75 ± 0.091.69 ± 0.051.70 ± 0.06.371
      Body mass index (kg/m2)
      Mean ± SD.
      28.4 ± 6.825.0 ± 4.827.0 ± 7.425.8 ± 5.4.541
      Hours in chair that day
      Mean ± SD.
      3.9 ± 2.13.1 ± 1.44.9 ± 2.45.9 ± 4.4
      Age range (y)22-4723-3824-5422-33
      a Mean ± SD.

      Products’ Attributes

      Participants were blinded to the manufacturers’ claims for each product being tested. They were told only that several different ergonomic chair support products would be compared. They were able to see the product as they sat down.
      The BackJoy SitSmart Relief product (BackJoy, Boulder, CO, USA) is made of a rigid hard plastic core with a cushioned cover. The pad is approximately 420 mm long × 320 mm wide × 10 mm thick. For this study, researchers used the black adult-sized product.
      The Spine Buddy LT1 H/C memory foam support pad (Spine Buddy, Humble, TX, USA) has a soft core with lateral enlargements at the lower back and neck regions to conform to the lordotic curves of the spine. The pad is approximately 540 mm long × 280 mm wide × 80 mm thick. The product has a Velcro strap that is used to affix it to chairs. Composite materials in the product allow the pad to be cooled or heated. For the cold pad analysis, researchers left the pad and cover in a portable Emerson CR500 freezer (Emerson Radio, Shandong, China) for 1 hour, as recommended by the manufacturer. For the heated pad analysis, the pad and cover were heated in a Hamilton Beach P100N30ALS3B 1000 W microwave (Galanz Electrical Appliances, Foshan City, China) for 30 seconds at high output, according to the manufacturer’s recommendations.

      Assessment

      Participants completed a baseline Nordic Musculoskeletal Questionnaire (NMQ).
      • Crawford J.
      The Nordic Musculoskeletal Questionnaire.
      • Dickinson C.
      • Campion K.
      • Foster A.
      • Newman S.
      • O’Rourke A.
      • Thomas P.
      Questionnaire development: an examination of the Nordic musculoskeletal questionnaire.
      • Kuorinka I.
      • Jonsson B.
      • Kilbom A.
      • et al.
      Standardised Nordic questionnaire for the analysis of musculoskeletal symptoms.
      The NMQ requires respondents to rate their pain/discomfort on a 1-5 scale, with 1 representing extremely comfortable and 5 representing extremely uncomfortable.
      • Crawford J.
      The Nordic Musculoskeletal Questionnaire.
      • Dickinson C.
      • Campion K.
      • Foster A.
      • Newman S.
      • O’Rourke A.
      • Thomas P.
      Questionnaire development: an examination of the Nordic musculoskeletal questionnaire.
      • Kuorinka I.
      • Jonsson B.
      • Kilbom A.
      • et al.
      Standardised Nordic questionnaire for the analysis of musculoskeletal symptoms.
      The instrument assesses pain/discomfort for the following 12 regions: eye, neck, shoulder, upper back, elbow, lower back, arm, wrist/hand, thigh, knee, calf, and foot/ankle. Although data were collected on all 12 regions, the focus of the study was limited to the neck, upper back, and lower back. Researchers intentionally did not reduce the 12 questions to 3 questions in an attempt to make it less likely that participants would remember the exact numbers they completed. After completing the NMQ posttest, participants were asked to recall the number of hours they had already sat in a chair that day.
      The chair used in this study was a black leather office executive chair (Office Star Products, Hong Kong, China) with armrests. Participants were not allowed to adjust the chair height. They were instructed not to move or swivel the chair. The chair height was set at 18 in from the inferior plastic shell of the underside of the seat to the floor. Duct tape on the floor was used to mark the exact location of each of the chair’s wheels to keep its position in the room similar for all study participants. Research subjects were told they could read while they waited for the 12 minutes to be completed. They had to keep their feet on the floor. Participants were instructed to remove any thick sweaters, coats, or similar items, as these would block the impact of the cold or hot Spine Buddy pads. Similarly, they were told that they could not wear a sports bra, cutoff shirt, or similar attire that would place the skin of their back directly against the chair and/or product.
      The participant sat in the chair for 12 minutes under 1 of the 4 following conditions: office chair only (control group), BackJoy SitSmart Relief and chair (experimental group 1), freezer-cooled Spine Buddy LT1 H/C and chair (experimental group 2), or microwave-heated Spine Buddy LT1 H/C and chair (experimental group 3). Twelve minutes was arbitrarily chosen because this is similar to the duration of some passive therapeutic modalities used in a chiropractic doctor’s office. Afterward, participants completed another NMQ and wrote down how many hours they sat in a chair that day. Participants attended only 1 study session.

      Environment

      This experiment occurred in a research laboratory with the ambient room temperature set to 74°F. We intentionally avoided playing music in the laboratory background during the study. This was done to avoid the possibility that the calming effect of some forms of music could act as a covariate for perception of pain.
      • Bradshaw D.
      • Chapman C.
      • Jacobson R.
      • Donaldson G.
      Effects of music engagement on responses to painful stimulation.

      Temperature Subanalysis Experiment

      Because of the unique properties of the Spine Buddy LT1 H/C product, we designed an experiment to analyze the temperature of the pad at baseline, as well as how quickly the temperature changed in relation to more commonly used clinical modalities. The Spine Buddy LT1 H/C product was heated or cooled as previously described and placed on a thinly carpeted floor. A Mainstays Quick-response thermometer (Mainstays, Guangdong, China) placed underneath the pad recorded the temperature at baseline (time 0), 6 minutes, and 12 minutes. For comparison, the same experiment was performed using a cold pack and hydrocollator pack at our college clinic. Both packs were wrapped under 8 layers of toweling to replicate common patient procedures employed in a chiropractic clinic.

      Statistical Analysis

      The data were analyzed in SPSS Version 20.0 (IBM, Armonk, NY, USA). Results are reported as the mean ± SD unless otherwise specified. A one-way analysis of variance (ANOVA) was used to compare between-group differences at baseline for age and anthropometric data. The Levene test of homogeneity of variances was observed. The α level of P ≤ .05 was considered statistically significant for between-group baseline data.
      A between-within repeated-measures ANOVA using the between-subject factor intervention (chair only, BackJoy SitSmart Relief, cooled Spine Buddy LT1 H/C, and heated Spine Buddy LT1 H/C) and within-subject factor time (baseline and posttest) was used to analyze study data. Mauchly’s test of sphericity was not observed because there were only 2 levels of the within-group repeated measure (pretest vs posttest).
      • Field A.
      Discovering statistics using SPSS.
      Levene’s test of equality of error variances was observed. A Bonferroni post hoc test was conducted on statistically significant data among all ANOVAs to determine which condition was significant.
      • Field A.
      Discovering statistics using SPSS.
      An α level of P ≤ .05 was considered statistically significant for all of these tests.

      Results

      Forty-eight participants completed this study. Comparison of baseline values of demographic and anthropometric variables revealed that for the 4 study group, there were no significant differences with respect to age (P = .875), mass (P = .705), height (P = .371), body mass index (P = .541), or number of hours that participants spent sitting in a chair earlier in the day before the study began (P = .082).
      All participants completed the baseline test and posttest (Fig 3). Box’s test of equality of covariance matrices was not significant for the neck pain (P = .120), upper back pain (P = .184), or lower back pain (P = .234) conditions. The main effect of “time” only across the whole sample was statistically significant for neck pain (F[1,44] = 24.766, P = .000, ηp2 = 0.360 [large effect size]), upper back pain (F[1,44] = 4.935, P = .032, ηp2 = 0.101 [moderate effect size]), and lower back pain (F[1,44] = 32.960, P = .000, ηp2 = 0.421 [large effect size]). However, no statistically significant interaction effect between intervention and time was observed. In other words, participants in all groups reported the same degree of pain relief after the experiment, with 1 exception: the participants in the control group reported slightly increased upper back pain on the posttest.
      Figure thumbnail gr3
      Fig 3Bar graph comparison of modifications in neck, upper back, and lower back pain among the 4 study groups on the Nordic Musculoskeletal Questionnaire (NMQ) Pain/Discomfort scale. Error bars represent individual SD per bar.
      The temperature subanalysis experiment (Fig 4) revealed that the Spine Buddy LT1 H/C pad was significantly less cold than an ice pack and less warm than a hydrocollator pack. The temperature subanalysis indicated that the Spine Buddy could neither be cooled to the same degree as a standard ice pack nor be heated to the same degree as a typical hydrocollator pack. The cooled pad began heating up and the heated pad began losing heat by the 12-minute mark. The standard cold pack and hydrocollator pack both maintained their baseline temperature for longer periods, indicating that they could provide cryotherapy and thermal therapy, respectively, for longer periods than the Spine Buddy support pad.
      Figure thumbnail gr4
      Fig 4Line graph comparison of temperature changes observed using the Spine Buddy LT1 H/C pad under the cooled and heated conditions (Δ = change). For the cooled condition, researchers cooled the pad for 1 hour and on a different day for 24 hours. This was done to compare the product’s maximal cooling potential with that of a household freezer.
      After the study was completed, researchers performed a post hoc power analysis using G*Power Version 3.1.3 (Universität Kiel, Kiel, Germany)
      • Faul F.
      • Erdfelder E.
      • Buchner A.
      • Lang A.
      Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses.
      • Erdfelder E.
      • Faul F.
      • Buchner A.
      GPOWER: A general power analysis program.
      with data from the spine region with the smallest group × time ηp2. This spine region was the lower back, with a group × time ηp2 of 0.090. An F-test family power analysis for the mixed ANOVA, with an effect size of 0.31 (as calculated with ηp2), using an α of .05, total sample size of 48, number of groups at 4, number of measurements at 2, correlation among repeated measures at 0.745 (derived from Pearson’s correlation between pretest and posttest lower back data), and nonsphericity correction of 1, indicated a power of 0.999 to detect significant change if it existed. This study indicated that in the short term, addition of the BackJoy SitSmart Relief and Spine Buddy LT1 H/C products to an office chair resulted in no appreciable improvements in bodywide pain in college students, compared with resting only on a chair with no additional therapeutic pads.

      Discussion

      Computer users and other individuals who sit at a desk for long periods are predisposed to develop neck pain,
      • Rempel D.
      • Krause N.
      • Goldberg R.
      • Benner D.
      • Hudes M.
      • Goldner G.
      A randomised controlled trial evaluating the effects of two workstation interventions on upper body pain and incident musculoskeletal disorders among computer operators.
      • Wahlström J.
      Ergonomics, musculoskeletal disorders and computer work.
      trapezius strain,
      • Rempel D.
      • Krause N.
      • Goldberg R.
      • Benner D.
      • Hudes M.
      • Goldner G.
      A randomised controlled trial evaluating the effects of two workstation interventions on upper body pain and incident musculoskeletal disorders among computer operators.
      • Wahlström J.
      Ergonomics, musculoskeletal disorders and computer work.
      back pain,
      • Harrison D.
      • Harrison S.
      • Croft A.
      • Harrison D.
      • Troyanovich S.
      Sitting biomechanics: Part I: Review of literature.
      • Callaghan J.
      • McGill S.
      Low back joint loading and kinematics during standing and unsupported sitting.
      • Sbriccoli P.
      • Solomonow M.
      • Zhou B.
      • et al.
      Static load magnitude is a risk factor in the development of cumulative low back disorder.
      • McGill S.M.
      • Hughson R.L.
      • Parks K.
      Lumbar erector spinae oxygenation during prolonged contractions: implications for prolonged work.
      and other regional musculoskeletal injuries. Some common risk factors for the development of these injuries are female gender, long work hours, repetitive motions, and sustained awkward desk postures.
      • Sauter S.
      • Schleifer L.
      • Knutson S.
      Work posture, workstation design, and musculoskeletal discomfort in a VDT data entry task.
      • Faucett J.
      • Rempel D.
      VDT-related musculoskeletal symptoms: interactions between work posture and psychosocial work factors.
      • Gerr F.
      • Marcus M.
      • Monteilh C.
      Epidemiology of musculoskeletal disorders among computer users: lesson learned from the role of posture and keyboard use.
      Various interventions have revealed a positive ability to reduce these types of desk-related injuries, including adjustable office chairs,
      • Nelson N.
      • Silverstein B.
      Workplace changes associated with a reduction in musculoskeletal symptoms in office workers.
      • Prabhu S.
      • Gandhi S.
      • Goddard P.
      Ergonomics of digital imaging.
      adjustable monitors,
      • Prabhu S.
      • Gandhi S.
      • Goddard P.
      Ergonomics of digital imaging.
      • Goyal N.
      • Jain N.
      • Rachapalli V.
      Ergonomics in radiology.
      ergonomic training,
      • Amick II, B.
      • Robertson M.
      • DeRango K.
      • et al.
      Effect of office ergonomics intervention on reducing musculoskeletal symptoms.
      • Brisson C.
      • Montreuil S.
      • Punnett L.
      Effects of an ergonomic training program on workers with video display units.
      • Westgaard R.
      • Winkel J.
      Ergonomic intervention research for improved musculoskeletal health: A critical review.
      regular work breaks,
      • Galinsky T.
      • Swanson N.
      • Sauter S.
      • Hurell Jr., J.
      • Schleifer L.
      A field study of supplementary rest breaks for data-entry operators.
      and lumbar supports.
      • Roelofs P.
      • Bierma-Zeinstra S.
      • van Poppel M.
      • et al.
      Lumbar supports to prevent recurrent low back pain among home care workers: a randomized trial.
      • Grondin D.
      • Triano J.
      • Tran S.
      • Soave D.
      The effect of a lumbar support pillow on lumbar posture and comfort during a prolonged seated task.
      Ultimately, the interventions used in this study did not improve participant outcomes.
      The closest studies that are similar to this project have involved lumbar supports. Roelofs et al. studied variables that predict adherence to lumbar support use.
      • Roelofs P.
      • Bierma-Zeinstra S.
      • van Poppel M.
      • et al.
      Lumbar supports to prevent recurrent low back pain among home care workers: a randomized trial.
      They pointed out that if participants are not regularly using the supports, they will not benefit from them. The strongest predictor they found for use was positive attitude toward using a lumbar support, which explained 41% of the variance (B = 1.31, P < .001) in their model. Self-efficacy (B = 0.22, P = .026) and social support (B = 0.39, P = .083) both played a minor role in adherence.
      Grondin et al. measured the impact of a lumbar support on seated comfort and lumbar posture.
      • Grondin D.
      • Triano J.
      • Tran S.
      • Soave D.
      The effect of a lumbar support pillow on lumbar posture and comfort during a prolonged seated task.
      They found that the lumbar support resulted in participants moving in their chair less often, as a measure of center of pressure discomfort changes (P = .017). Additionally, lumbar flattening was decreased by using a lumbar support in their study (P = .006).
      Makhsous et al. analyzed the impact of an adjustable ischial and lumbar support on occupational low back pain.
      • Makhsous M.
      • Lin F.
      • Bankard J.
      • Hendrix R.
      • Hepler M.
      • Press J.
      Biomechanical effects of sitting with adjustable ischial and lumbar support on occupational low back pain: evaluation of sitting back muscle activity.
      They found that the addition of a support significantly pushed seated center of force and peak pressure anteriorly (P < .001), and participants placed more pressure against the back of the seat (P < .01). As a result, less direct force was being exerted on the lower back in an axial direction. Because of this action, muscle activity in the lumbar spine decreased significantly. They theorized that this would help patients with sitting-related low back pain. A difference between our study and this study would be participant pain level. Makhsous et al. used participants with a greater amount of pain as measured by Oswestry Low Back Pain Disability Questionnaire and Roland-Morris Low Back Pain Disability Questionnaire.
      The Spine Buddy LT1 H/C chair support is designed to be cooled or heated to help provide pain relief. One possible reason that the pain-relieving benefits of cryotherapy or thermotherapy were not visible with this product may have been its failure to reach adequate therapeutic temperatures. MacAuley suggests that cryotherapy must be cool enough to lower tissue temperature by 10°F to 15°F to produce optimal therapeutic effects.
      • MacAuley D.
      Ice therapy: How good is the evidence?.
      Researchers discovered that although the pad was stored in a freezer for 1 hour before each participant was tested, it warmed to room temperature quickly when placed against a participant’s back. That observation specifically drove researchers to add the temperature comparison subanalysis to this study. It appears that the Spine Buddy LT1 H/C chair support with its current build design cannot achieve temperatures that are cold
      • MacAuley D.
      Ice therapy: How good is the evidence?.
      or hot
      • Currier D.
      • Kramer J.
      Sensory nerve conduction: heating effects of ultrasound and infrared radiation.
      enough to yield therapeutic benefits, as can the typical cold pack or hydrocollator pack.
      Future directions of research should include studies measuring (1) how different chair supports affect spine-related pain over extended use (hours to days), (2) how varying chair supports affect lumbar lordotic curve, and (3) variables that are determinants of lumbar support adherence.
      • Roelofs P.
      • van Poppel M.
      • Bierma-Zeinstra S.
      • van Mechelen W.
      Determinants of the intention for using a lumbar support among home care workers with recurrent low back pain.

      Limitations

      One limitation of this study may be that participants did not have elevated neck or back pain levels. The lack of significant baseline pain might have masked to some degree the capabilities of the products to reduce pain. A more ideal study would be to recruit participants with neck or back pain.
      Another limitation was the use of an ergonomic office chair in this study. Researchers attempted to use a typical office chair, but depending on where someone worked, they may have a more rigid office chair. If a harder, less cushioned chair had been used, it may have made a difference for the Spine Buddy product compared with the BackJoy product because the latter product has minimal cushioning.
      We cannot confirm or deny the claim that the BackJoy product increases lumbar lordotic curve in a seated position, as no such biomechanics study was performed.
      This study was not supported by a grant from either company. However, the Spine Buddy company has funded small projects on their products at the researcher’s college before. Because one company has funded projects on the researcher’s campus and the other has not, the researchers cannot claim zero bias existed. However, the researchers made no attempt to verbally encourage participants to have a more positive outlook toward one product compared with the other. The findings of this study revealed that neither product resulted in a greater positive impact on pain.
      Participants were not blinded in the study. They were able to see the pad they were going to lie against on the chair.
      Lastly, the 12 minutes used in this study may have been an insufficient period to garner any appreciable benefit from a chair support pad compared with the control chair with no pad. Perhaps consumers would need to sit on a chair support pad for a few hours to significantly benefit from the product. An argument can also be made that time was an issue for the Spine Buddy product because typical treatment protocols for cold packs and hydrocollator packs are 20 minutes and 15 to 20 minutes, respectively.
      • Prentice W.
      Therapeutic Modalities in Rehabilitation.
      However, as has already been discussed, the temperatures achieved by the Spine Buddy product were significantly less than those of an ice pack or hydrocollator pack, which likely nullifies this argument.

      Conclusion

      These preliminary results suggest that the addition of an extra support to an office chair may not necessarily reduce neck or back pain when used for brief periods. Additionally, although the Spine Buddy LT1 H/C can be cooled or heated, the existing temperature guidelines provided by the manufacturer do not reach physiologic levels associated with significant reductions in pain.

      Funding Sources and Conflicts of Interest

      This research project was not supported by a research grant; however, the investigators have received grants from the Spine Buddy Company for previous research experiments. No other conflicts were reported for this study.

      Contributorship Information

      • Concept development (provided idea for the research): J.W., J.C.
      • Design (planned the methods to generate the results): J.W., J.C.
      • Supervision (provided oversight, responsible for organization and implementation, writing of the manuscript): J.W., J.C.
      • Data collection/processing (responsible for experiments, patient management, organization, or reporting data): J.W., J.C.
      • Analysis/interpretation (responsible for statistical analysis, evaluation, and presentation of the results): J.W.
      • Literature search (performed the literature search): J.W.
      • Writing (responsible for writing a substantive part of the manuscript): J.W.
      • Critical review (revised manuscript for intellectual content, this does not relate to spelling and grammar checking): J.W.

      Practical Applications

      • Addition of a support pad/product to an office chair did not have an additive impact on neck or back pain for the group of patients tested.
      • There was no difference between the effects of the BackJoy SitSmart Relief and the Spine Buddy LT1 H/C pads on patient pain outcomes.

      Acknowledgments

      The investigative team thanks Claire Noll for assistance with editing.

      References

        • Lin C.
        • Haas M.
        • Maher C.
        • Machado L.
        • van Tulder M.
        Cost-effectiveness of guideline-endorsed treatments for low back pain: a systematic review.
        Eur Spine J. 2011; 20: 1024-1038
        • Dagenais S.
        • Caro J.
        • Haldeman S.
        A systematic review of low back pain cost of illness studies in the United States and internationally.
        Spine J. 2008; 8: 8-20
        • Lerner D.
        • Rogers W.
        • Chang H.
        • et al.
        The health care and productivity costs of back and neck pain in a multi-employer sample of utility industry employees.
        J Occup Environ Med. 2015; 57: 32-43
        • Serrano-Aguilar P.
        • Kovacs F.
        • Cabrera-Hernández J.
        • Ramos-Goñi J.
        • García-Pérez L.
        Available costs of physical treatments for chronic back, neck, and shoulder pain within the Spanish National Health Service: a cross-sectional study.
        BMC Musculoskelet Disord. 2011; 12: 287
        • Tüzün E.
        Quality of life in chronic musculoskeletal pain.
        Best Pract Res Clin Rheumatol. 2007; 21: 567-579
        • Linton S.
        A review of psychosocial risk factors in back and neck pain.
        Spine (Phila Pa 1976). 2000; 25: 1148-1156
        • Scholich S.
        • Hallner D.
        • Wittenberg R.
        • Hasenbring M.
        • Rusu A.
        The relationship between pain, disability, quality of life and cognitive behavioral factors in chronic back pain.
        Disabil Rehabil. 2012; 34: 1993-2000
        • Carroll L.
        • Hogg-Johnson S.
        • van der Velde G.
        • et al.
        Course and prognostic factors for neck pain in the general population: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders.
        Spine (Phila Pa 1976). 2008; 33: S75-S82
        • Hoy D.
        • Bain C.
        • Williams G.
        • et al.
        A systematic review of the global prevalence of low back pain.
        Arthritis Rheum. 2012; 64: 2028-2037
        • Beaudet N.
        • Courteau J.
        • Sarret P.
        • Vanasse A.
        Prevalence of claims-based recurrent low back pain in a Canadian population: a secondary analysis of an administrative database.
        BMC Musculoskelet Disord. 2013; 14: 151
        • Ricci J.
        • Stewart W.
        • Chee E.
        • Leotta C.
        • Foley K.
        • Hochberg M.
        Back pain exacerbations and lost productive time costs in United States workers.
        Spine (Phila Pa 1976). 2006; 31: 3052-3060
        • Furlan A.
        • Yazdi F.
        • Tsertsvadze A.
        • et al.
        A systematic review and meta-analysis of efficacy, cost-effectiveness, and safety of selected complementary and alternative medicine for neck and low-back pain.
        Evid Based Complement Alternat Med. 2012; 2012: 953139
        • Murtezani A.
        • Hundozi H.
        • Orovcanec N.
        • Berisha M.
        • Meka V.
        Low back pain predict sickness absence among power plant workers.
        Indian J Occup Environ Med. 2010; 14: 49-53
        • Hoogendoorn W.
        • Bongers P.
        • de Vet H.
        • Ariëns G.
        • van Mechelen W.
        • Bouter L.
        High physical work load and low job satisfaction increase the risk of sickness absence due to low back pain: results of a prospective cohort study.
        Occup Environ Med. 2002; 59: 323-328
        • Infante-Rivard C.
        • Lortie M.
        Relapse and short sickness absence for back pain in the six months after return to work.
        Occup Environ Med. 1997; 54: 328-334
        • Punnett B.
        • Greenidge D.
        • Ramsey J.
        Job attitudes and absenteeism: a study in the English speaking Caribbean.
        J World Bus. 2007; 42: 214-227
        • Aronsson G.
        • Gustafsson K.
        • Dallner M.
        Sick but yet at work: an empirical study of sickness presenteeism.
        J Epidemiol Community Health. 2000; 54: 502-509
        • Johns G.
        Presenteeism in the workplace: a review and research agenda.
        J Organ Behav. 2010; 31: 519-542
        • Bostrom M.
        • Dellve L.
        • Thomee S.
        • Hagberg M.
        Risk factors for generally reduced productivity: a prospective cohort study of young adults with neck or upper-extremity musculoskeletal symptoms.
        Scand J Work Environ Health. 2008; 34: 120-132
        • Hagberg M.
        • Vilhelmsson R.
        • Tornqvist E.
        • Toomingas A.
        Incidence of self-reported reduced productivity owing to musculoskeletal symptoms: association with workplace and individual factors among computer users.
        Ergonomics. 2007; 50: 1820-1834
      1. BackJoy: SitSmart Relief [Internet]. Boulder, CO: BackJoy; c2010-2015. Available at http://www.backjoy.com/sit-products/. Accessed March 1, 2015.

      2. Spine Buddy: Spine Buddy LT1 H/C memory foam chair support [Internet]. Humble, TX: Spine Buddy; c2014-2015. Available at http://www.myspinebuddy.com. Accessed February 1, 2015.

        • Pynt J.
        • Mackey M.
        • Higgs J.
        Kyphosed seated postures: extending concepts of postural health beyond the office.
        J Occup Rehabil. 2008; 18: 35-45
        • Harrison D.
        • Harrison S.
        • Croft A.
        • Harrison D.
        • Troyanovich S.
        Sitting biomechanics: Part I: Review of literature.
        J Manipulative Physiol Ther. 1999; 22: 594-609
        • Lord M.
        • Small J.
        • Dinsay J.
        • Watkins R.
        Lumbar lordosis: effects of sitting and standing.
        Spine (Phila Pa 1976). 1997; 22: 2571-2574
        • Andersson G.
        • Murphy R.
        • Ortengren R.
        • Nachemson A.
        The influence of backrest inclination and lumbar support on lumbar lordosis.
        Spine (Phila Pa 1976). 1979; 4: 52-58
        • Andersson B.
        • Örtengren R.
        Lumbar disc pressure and myoelectric back muscle activity during sitting: II. Studies on an office chair.
        Scand J Rehabil Med. 1974; 6: 115-121
        • Keegan J.
        Alterations of the lumbar curve related to posture and seating.
        J Bone Joint Surg. 1953; 35-A: 589-603
        • Ward J.
        • Coats J.
        • Pourmoghaddam A.
        Spine buddy® supportive pad impact on single-leg static balance and jogging gait of individuals wearing a military backpack.
        J Hum Kinet. 2014; 44: 7-20
        • Ward J.
        • Coats J.
        Anterior-to-posterior protective capabilities of the Spine Buddy® jockey vest support pad.
        Top Integr Health Care. 2014; 5 (ID:5.4002)
        • Ward J.
        • Coats J.
        • Devers A.
        • Murphy B.
        Supportive pad impact on upper extremity blood flow while wearing a military backpack.
        Top Integr Health Care. 2014; 5 (ID:5.2003)
        • Selkow N.
        • Day C.
        • Liu Z.
        • Hart J.
        • Hertel J.
        • Saliba S.
        Microvascular perfusion and intramuscular temperature of the calf during cooling.
        Med Sci Sports Exerc. 2012; 44: 850-856
        • Mila-Kierzenkowska C.
        • Jurecka A.
        • Woźniak A.
        • Szpinda M.
        • Augustyńska B.
        • Woźniak B.
        The effect of submaximal exercise preceded by single whole-body cryotherapy on the markers of oxidative stress and inflammation in blood of volleyball players.
        Oxid Med Cell Longev. 2013; 2013: 409567
        • de Jong R.
        • Hershey W.
        • Wagman I.
        Nerve conduction velocity during hypothermia in man.
        Anesthesiology. 1966; 27: 805-810
        • Eldred E.
        • Lindsley D.
        • Buchwald J.
        The effect of cooling on mammalian muscle spindles.
        Exp Neurol. 1960; 2: 144-157
        • Lippold O.
        • Nicholls J.
        • Redfearn J.
        A study of the afferent discharge produced by cooling a mammalian muscle spindle.
        J Physiol. 1960; 153: 218-231
        • Prentice W.
        Therapeutic Modalities in Rehabilitation.
        4th ed. McGraw-Hill, New York2011
        • Mense S.
        Effects of temperature on the discharges of muscle spindles and tendon organs.
        Pflugers Arch. 1978; 374: 159-166
        • DeVries H.
        Quantitative electromyographic investigation of the spasms theory of muscle pain.
        Am J Phys Med. 1966; 45: 119-134
        • Mendell L.
        Constructing and deconstructing the gate theory of pain.
        Pain. 2014; 155: 210-216
        • Deliens T.
        • Deforche B.
        • Bourdeaudhuij I.
        • Clarys P.
        Determinants of physical activity and sedentary behavior in university students: a qualitative study using focus group discussions.
        BMC Public Health. 2015; 15: 201
        • Crawford J.
        The Nordic Musculoskeletal Questionnaire.
        Occup Med. 2007; 57: 300-301
        • Dickinson C.
        • Campion K.
        • Foster A.
        • Newman S.
        • O’Rourke A.
        • Thomas P.
        Questionnaire development: an examination of the Nordic musculoskeletal questionnaire.
        Appl Ergon. 1992; 23: 197-201
        • Kuorinka I.
        • Jonsson B.
        • Kilbom A.
        • et al.
        Standardised Nordic questionnaire for the analysis of musculoskeletal symptoms.
        Appl Ergon. 1987; 18: 233-237
        • Bradshaw D.
        • Chapman C.
        • Jacobson R.
        • Donaldson G.
        Effects of music engagement on responses to painful stimulation.
        Clin J Pain. 2012; 28: 418-427
        • Field A.
        Discovering statistics using SPSS.
        2nd ed. Sage, Thousand Oaks, CA2005
        • Faul F.
        • Erdfelder E.
        • Buchner A.
        • Lang A.
        Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses.
        Behav Res Methods. 2009; 41: 1149-1160
        • Erdfelder E.
        • Faul F.
        • Buchner A.
        GPOWER: A general power analysis program.
        Behav Res Methods Instrum Comput. 1996; 28: 1-11
        • Rempel D.
        • Krause N.
        • Goldberg R.
        • Benner D.
        • Hudes M.
        • Goldner G.
        A randomised controlled trial evaluating the effects of two workstation interventions on upper body pain and incident musculoskeletal disorders among computer operators.
        Occup Environ Med. 2006; 63 (Erratum in Occup Environ Med. 2006; 63:856): 300-306
        • Wahlström J.
        Ergonomics, musculoskeletal disorders and computer work.
        Occup Med. 2005; 55: 168-176
        • Callaghan J.
        • McGill S.
        Low back joint loading and kinematics during standing and unsupported sitting.
        Ergonomics. 2001; 44: 280-294
        • Sbriccoli P.
        • Solomonow M.
        • Zhou B.
        • et al.
        Static load magnitude is a risk factor in the development of cumulative low back disorder.
        Muscle Nerve. 2004; 29: 300-308
        • McGill S.M.
        • Hughson R.L.
        • Parks K.
        Lumbar erector spinae oxygenation during prolonged contractions: implications for prolonged work.
        Ergonomics. 2000; 43: 486-493
        • Sauter S.
        • Schleifer L.
        • Knutson S.
        Work posture, workstation design, and musculoskeletal discomfort in a VDT data entry task.
        Hum Factors. 1991; 33: 151-167
        • Faucett J.
        • Rempel D.
        VDT-related musculoskeletal symptoms: interactions between work posture and psychosocial work factors.
        Am J Ind Med. 1994; 26: 597-612
        • Gerr F.
        • Marcus M.
        • Monteilh C.
        Epidemiology of musculoskeletal disorders among computer users: lesson learned from the role of posture and keyboard use.
        J Electromyogr Kinesiol. 2004; 14: 25-31
        • Nelson N.
        • Silverstein B.
        Workplace changes associated with a reduction in musculoskeletal symptoms in office workers.
        Hum Factors. 1998; 40: 337-350
        • Prabhu S.
        • Gandhi S.
        • Goddard P.
        Ergonomics of digital imaging.
        Br J Radiol. 2005; 78: 582-586
        • Goyal N.
        • Jain N.
        • Rachapalli V.
        Ergonomics in radiology.
        Clin Radiol. 2009; 64: 119-126
        • Amick II, B.
        • Robertson M.
        • DeRango K.
        • et al.
        Effect of office ergonomics intervention on reducing musculoskeletal symptoms.
        Spine (Phila Pa 1976). 2003; 28: 2706-2711
        • Brisson C.
        • Montreuil S.
        • Punnett L.
        Effects of an ergonomic training program on workers with video display units.
        Scand J Work Environ Health. 1999; 25: 255-263
        • Westgaard R.
        • Winkel J.
        Ergonomic intervention research for improved musculoskeletal health: A critical review.
        Int J Ind Ergon. 1997; 20: 463-500
        • Galinsky T.
        • Swanson N.
        • Sauter S.
        • Hurell Jr., J.
        • Schleifer L.
        A field study of supplementary rest breaks for data-entry operators.
        Ergonomics. 2000; 43: 622-638
        • Roelofs P.
        • Bierma-Zeinstra S.
        • van Poppel M.
        • et al.
        Lumbar supports to prevent recurrent low back pain among home care workers: a randomized trial.
        Ann Intern Med. 2007; 147: 685-692
        • Grondin D.
        • Triano J.
        • Tran S.
        • Soave D.
        The effect of a lumbar support pillow on lumbar posture and comfort during a prolonged seated task.
        Chiropr Man Therap. 2013; 21: 21
        • Makhsous M.
        • Lin F.
        • Bankard J.
        • Hendrix R.
        • Hepler M.
        • Press J.
        Biomechanical effects of sitting with adjustable ischial and lumbar support on occupational low back pain: evaluation of sitting back muscle activity.
        BMC Musculoskelet Disord. 2009; 10: 17
        • MacAuley D.
        Ice therapy: How good is the evidence?.
        Int J Sports Med. 2001; 22: 379-384
        • Currier D.
        • Kramer J.
        Sensory nerve conduction: heating effects of ultrasound and infrared radiation.
        Physiother Can. 1982; 34: 241-246
        • Roelofs P.
        • van Poppel M.
        • Bierma-Zeinstra S.
        • van Mechelen W.
        Determinants of the intention for using a lumbar support among home care workers with recurrent low back pain.
        Eur Spine J. 2010; 19: 1502-1507