Muscle Strength In Subjects Research Articles

The relationship between femoral cartilage thickness and muscle strength in knee osteoarthritis.

To explore whether femoral cartilage thickness is related (and changes) with muscle strength in subjects with knee osteoarthritis (OA). Forty patients (27F, 13M) with knee OA-who were under quadriceps muscle strengthening program-were enrolled in the study. Isokinetic/isometric knee muscle strength measurements (at 30-60° angles and 60-180° velocity) were performed at baseline, end of the muscle strengthening program, and third month control visit using a biodex dynamometer. Femoral cartilage thicknesses (at medial/lateral condyle and intercondylar area) were measured using ultrasonography. Seventy-nine knees of 40 patients (27 F, 13 M) aged 52.03 ± 11.72years (range, 26-71) were analyzed. Mean VAS scores on the first and third months were significantly lower than the initial values (p < 0.001, p = 0.049). Isometric peak torque and total work values at 180°/s were significantly higher than the baseline measurements at first and third month controls (all p < 0.05). Cartilage thicknesses (at three sites) were significantly higher than the baseline measurements (all p < 0.05) on the third month but not on the first month (all p > 0.05). Femoral cartilage thicknesses were positively correlated with isometric strength values at baseline and third month. We propose that femoral cartilage thicknesses increase on the third month of strengthening therapy. Since this late-phase thickening parallels the earlier increase in muscle strength (starting, on the first month), we speculate that regeneration rather than edema might be the primary underlying cause.

The Correlation of Skeletal and Cardiac Muscle Dysfunction in Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is characterized by progressive skeletal muscle and cardiac dysfunction. While skeletal muscle dysfunction precedes cardiomyopathy, the relationship between the progressive decline in skeletal and cardiac muscle function is unclear. This relationship is especially important given that the myocardial effects of many developing DMD therapies are largely unknown. Our objective was to assess the relationship between progression of skeletal muscle weakness and onset of cardiac dysfunction in DMD. A total of 77 DMD subjects treated at a single referral center were included. Demographic information, quantitative muscle testing (QMT), subjective muscle strength, cardiac function, and current and retrospective medications were collected. A Spearman rank correlation was used to evaluate for an association between subjective strength and fractional shortening. The effects of total QMT and arm QMT on fractional shortening were examined in generalized least square with and without adjustments for age, ambulatory status, and duration of corticosteroids and cardiac specific medications. We found a significant correlation between maintained subjective skeletal muscle arm and leg strength and maintained cardiac function as defined by fractional shortening (rho=0.47, p=0.004 and rho=0.48, p=0.003, respectively). We also found a significant association between QMT and fractional shortening among non-ambulatory DMD subjects (p=0.03), while this association was not significant in ambulatory subjects. Our findings allow us to conclude that in this population, there exists a significant relationship between skeletal muscle and cardiac function in non-ambulatory DMD patients. While this does not imply a causal relationship, a possible association between skeletal and cardiac muscle function suggests that researchers should carefully monitor cardiac function, even when the primary outcome measures are not cardiac in nature.

TO STUDY THE EFFECT OF PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION ON BACK MUSCLE STRENGTH, PAIN AND QUALITY OF LIFE IN SUBJECTS WITH CHRONIC LOW BACK PAIN – AN EXPERIMENTAL STUDY

Background:&nbsp;Back pain is a prevalent and expensive problem in society. 60-80% of people will suffer at least one episode of low back pain sometime in their lives and 30-40% of these will experience low back pain each year. Therefore the need of the following study is to see the effect of proprioceptive neuromuscular facilitation on back muscle strength, pain and QOL in subjects with Chronic Low Back Pain.Methods: Ethical approval was taken before study. Forty patients with chronic low back pain (28 male, 12 female) were included in the study and divided into two groups each containing 20 subjects. All the participants were signed written consent after being informed in detail about the study. Group A has been given the proprioceptive neuromuscular facilitation exercises including Rhythmic Stabilization (RST) and Combination of Isotonics (COI) and Conventional back exercises. Group B was given conventional back exercises only. Outcome measures were taken at the end of one month i.e. after the treatment protocol. VAS, SF-36Questionnaire and Core stability gradation were taken in both groups.Results:&nbsp;There is significant improvement in VAS score in both groups but Group A was having more significant improvement than Group B. Also there is significant improvement in core stability grading and SF 36 score in Group A.Conclusion:&nbsp;It is concluded that proprioceptive neuromuscular facilitation exercises on back is effective in reducing pain and improving core muscle strength in subjects with Chronic Low Back Pain.

Changes In Muscle Strength In Individuals With Statin-induced Myopathy

Changes In Muscle Strength In Individuals With Statin-induced Myopathy

Brain-derived neurotrophic factor correlated with muscle strength in subjects undergoing stationary bicycle exercise training

AimsSeveral central nervous disorders are associated with metabolic syndrome (MetS) and type 2 diabetes. Reduction in brain-derived neurotrophic factor (BDNF) is involved in the mechanism of central nervous dysfunction. BDNF is up-regulated after exercise, but it is not known whether increased BDNF is related to increases in muscle strength. MethodsIn the present study, subjects with MetS or type 2 diabetes were enrolled in an exercise program. All participants underwent an indoor bicycle exercise program for twelve weeks. Serum BDNF was determined after overnight fasting. Muscle strength was assessed by extension of the dominant lower extremity. ResultsA total of 33 subjects were enrolled in this study. The body mass index did not change significantly (from 30.4±6.0 to 30.2±5.8kg/m2, P=0.436), but serum BDNF increased significantly (from 17.1±9.1 to 24.2±10.7ng/mL, P<0.001) after the study. The exercise-associated BDNF was significantly correlated with the increased strength in lower-extremity extension test (r=0.54, P=0.001). Using multivariate regression analysis, muscle-strength increment, but not body-weight change, was an independent factor for serum BDNF (95% CI=0.009–0.044, P=0.005). ConclusionsAfter a twelve-week program of stationary bicycle exercise, serum BDNF concentration increased, and this change was positively correlated with muscle strength of lower-extremity extension, but not body weight. (Trial registration: NCT02268292, ClinicalTrials.gov)

Changes in muscle strength in individuals with statin-induced myopathy: A summary of 3 investigations

There are inconsistent findings regarding muscular weakness in individuals with statin-induced myalgia. We used rigorous muscle testing to compare findings from 3 investigations in 3 different study populations to determine if statin myalgia is associated with measurable weakness. In all 3 studies, we measured maximal isometric handgrip strength, resting respiratory exchange ratio (RER), and knee extensor isometric and isokinetic force. In 2 of the 3 studies, elbow flexor isometric and isokinetic force and knee endurance fatigue index were also assessed. Knee extensor and elbow flexor measurements were obtained using an isokinetic dynamometer. Resting RER was measured using a metabolic breath-by-breath collection method. Measurement outcomes were compared on vs off drug. In study 1, 18 participants fit the criteria for statin myalgia. Participants taking atorvastatin 80mg daily had significantly lower muscle strength in 5 (P<.05) of 14 measured variables. Participants on placebo (N=10) with myalgia had significantly lower muscle strength in 4 (P<.05) of 14 measured variables. In study 2, 18 participants tested positive for statin-induced myalgia when receiving simvastatin 20mg daily and displayed no significant muscle strength changes (all P>.05). In study 3, 11 patients with statin-induced myalgia completed the study and had a significant decrease in 2 (P<.05) of 10 leg muscle strength variables. In all 3 studies, no significant changes were shown for handgrip strength or RER (all P>.05). Our results indicate that after a short-term treatment with statin therapy, a rigorous muscle strength protocol does not show decrements of muscle strength in subjects with statin myalgia. Short-term treatment with statin therapy is not common in clinical practice. Thus, future studies should examine the effects of prolonged statin therapy on muscle strength.

Reliability and validity of the modified sphygmomanometer test for the assessment of strength of upper limb muscles after stroke.

To investigate the reliability (test-retest and inter-rater) and criterion-related validity of the modified sphygmomanometer test (MST) for the assessment of upper limb muscle strength in subjects with chronic stroke, and to determine whether the results are affected by the number of trials. The strength of 11 upper limb muscle groups of 57 subjects with stroke was bilaterally assessed with portable dynamometers and the MST (measured in mmHg). To investigate whether the number of trials would affect the results, 1-way analysis of variance was applied. For the test-retest/inter-rater reliabilities and criterion-related validity of the MST, intra-class correlation coefficients (ICCs), Pearson's correlation coefficients, and coefficients of determination were calculated. Different numbers of trials provided similar values for all assessed muscles (0.01 ≤ F ≤ 0.18; 0.83 ≤ p ≤ 0.99) with adequate test-retest (0.83 ≤ ICC ≤ 0.97; p < 0.0001) and inter-rater reliabilities (0.79 ≤ ICC ≤ 0.97; p < 0.0001) and validity (0.61 ≤ r ≤ 0.95; p < 0.0001). The values obtained with the MST were good predictors of those obtained with portable dynamometers (0.60 ≤ r2 ≤ 0.86), except for pinch strength (0.39 ≤ r2 ≤ 0.54). The MST showed adequate measurement properties for the assessment of the strength of the upper limb muscles of subjects with chronic stroke. After familiarization a single trial provided adequate strength values.

Comparison of pulmonary function and back muscle strength according to the degree of spinal curvature of healthy adults.

[Purpose] Degree of curvature on the spine is known to affect respiratory function and back muscle activation. We compared pulmonary function and back muscle strength according to the degree of curvature of the spine of healthy adults. [Subjects and Methods] Twenty-three healthy volunteers were enrolled. They were divided into two groups according to the degree of curvature of the spine: the below 2° group, and the above 2° group. The degree of curvature was assessed using the Adams forward bending test and a scoliometer. A pulmonary function test (PFT) was conducted, and back muscle strength was measured. [Results] No significant differences in PFT were found between the below 2° group and the above 2° group, in terms of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC), or peak expiratory flow (PEF). However, back muscle strength in the below 2 group was significantly higher than that of the above 2 group. [Conclusion] Our findings indicate that the degree of curvature of the spine is associated with back muscle strength in subjects who have spinal curvature within the normal range. Therefore, evaluation and treatment of back muscle strength might be helpful for preventing the progress of curvature of the spine in adolescents with potential scoliosis.

Reduction of respiratory muscle strength in subjects with rheumatoid arthritis

Objective: To evaluate the respiratory muscle strength in patients with rheumatoid arthritis (RA) compared to healthy subjects and to correlate it with the level of disease activity (DAS- 28) and body mass index (BMI). Method: A cross-sectional study evaluated 18 women (57.94 ± 10.36 years); eight had RA (RA group) and ten were healthy subjects (control group), matched by age. All patients underwent the following evaluations: registration form (identification and clinical data), physical examination (weight, height, and BMI), DAS-28, dosage of C-reactive protein (CRP), and measurement of MIP and MEP with a manometer. Results: There were significant differences between the RA and control groups in relation to the MIP (-46.25 ± 17.67 vs. cmH2O -81.00 ± 19.69 cm H2O) and MEP (58.75 cmH2O ± 17.26 vs. 78.00 ± 6.32 cmH2O). Also there was difference between RA group and predicted age values in relation to the MIP (-46.25 ± 17.67 vs. -81.06 ± 4.11 cmH2O) and MEP (58.75 cmH2O ± 17.26 vs. 78.92 ± 5.33 cmH2O). Moreover, a significant correlation was observed between MEP and BMI. There was no significant correlation between MIP - CRP, DAS- 28 and BMI, and between MEP - DAS and CRP. Conclusion: This data reinforces the systemic nature of RA and points out the need for a comprehensive assessment of the patient, not just focusing on the articular component, but also checking the strength of the respiratory muscles of these individuals to determine more specific therapeutic strategies of treatment.

Inspiratory muscle strength in subjects with tetraplegia: viability of evaluation through the measurement of maximal inspiratory pressure

Objective To analyze the values of maximal inspiratory pressure (MIP) and sniff nasal inspiratory pressure (SNIP) and to verify the existence of concordance between the two evaluation methodologies, in subjects with tetraplegia. Materials and methods Cross-sectional study with 17 tetraplegic men, aged 30.42 ± 7.67 years, who underwent MIP and SNIP evaluation using a respiratory pressure meter. Results The MIP and SNIP values obtained showed no difference when compared to each other (88.42 ± 29.39 vs. 86.68 ± 25.40 cmH2O, respectively). They were, however, significantly lower compared to the predicted values (MIP = 128.92 ± 7.18; SNIP = 114.11 ± 3.19 cmH2O), with the MIP values presenting correlation (r2 = 0.94; p &lt; 0.0001) and concordance with those of the SNIP. Conclusions Both the MIP and SNIP values obtained were lower than the predicted values, indicating a reduction in inspiratory muscle strength (IMS). Both techniques showed correlation and concordance, suggesting that MIP can be used as a noninvasive method for IMS evaluation in this population.

Impact of physical treatment and medicamentous therapy on muscle strength in subjects with lower bone density

Impact of physical treatment and medicamentous therapy on muscle strength in subjects with lower bone density

Expiratory and expiratory plus inspiratory muscle training improves respiratory muscle strength in subjects with COPD: systematic review.

Inspiratory muscle training (IMT) produces beneficial effects in COPD subjects, but the effects of expiratory muscle training (EMT) and EMT plus IMT in ventilatory training are still unclear. The aim of this study was to systematically review the effects of EMT and EMT plus IMT compared to control groups of COPD subjects. This study is a systematic review and meta-analysis. The search strategy included MEDLINE, Embase, LILACS, PEDro, and Cochrane CENTRAL and also manual search of references in published studies on the subject. Randomized trials comparing EMT and EMT plus IMT versus control groups of subjects with COPD were included. The outcomes analyzed were respiratory muscle strength and functional capacity. Two reviewers independently extracted the data. The search retrieved 609 articles. Five studies were included. We observed that EMT provided higher gain in maximum expiratory pressure (P(E(max)) 21.49 cm H2O, 95% CI 13.39-29.59) and maximum inspiratory pressure (P(I(max)) 7.68 cm H2O, 95% CI 0.90-14.45) compared to control groups. There was no significant difference in the 6-min walk test distance (29.01 m, 95% CI -39.62 to 97.65) and dyspnea (0.15, 95% CI -0.77 to 1.08). In relation to EMT plus IMT, we observed that P(E(max)) (31.98 cm H2O, 95% CI 26.93-37.03) and P(I(max)) (27.98 cm H2O, 95% CI 20.10-35.85) presented higher values compared to control groups. EMT and EMT plus IMT improve respiratory muscle strength and can be used as part of the treatment during pulmonary rehabilitation of subjects with severe to very severe COPD.

Reduction of respiratory muscle strength in subjects with rheumatoid arthritis

Objetivo: Avaliar a força muscular respiratória de pacientes com Artrite Reumatoide (AR) em comparação a indivíduos saudáveis e correlacionar com o nível de atividade da doença (DAS-28) e índice de massa corporal (IMC). Método: Estudo transversal onde foram avaliadas 18 mulheres, com média de idade de 57,94 anos, sendo 8 com AR (Grupo AR) e 10 saudáveis (Grupo Controle), pareadas por idade. Todas foram submetidas às seguintes avaliações: ficha cadastral - dados de identificação e clínicos; exame físico - massa corporal, estatura e IMC; DAS-28; dosagem de proteína C-reativa (PCR) e determinação dos valores de Pressão Inspiratória Máxima (PImáx) e Pressão Expiratória Máxima (PEmáx), por meio de um manovacuômetro. Foi adotado o nível de significância de 5%. Resultados: Houve diferença estatisticamente significativa entre os grupos AR e Controle em relação à PImáx (-46,25 ± 17,67 cmH2O vs. -81,00 ± 19,69 cmH2O; p ≤ 0,01) e PEmáx (58,75 ± 17,26 cmH2O vs. 78,00 ± 6,32 cmH2O; p ≤ 0,01). Também verificou-se diferença entre o grupo AR e valores preditos para a idade em relação à PImáx (-46,25 ± 17,67 cmH2O vs. -81,06 ± 4,11 cmH2O; p ≤ 0,01) e PEmáx (58,75 ± 17,26 cmH2O vs. 78,92 ± 5,33 cmH2O; p ≤ 0,01). Adicionalmente, foi encontrada correlação significativa entre a PEmáx e IMC (p = 0,03). Não houve correlação significativa entre as variáveis PImáx - PCR, DAS-28 e IMC, e entre PEmáx - DAS e PCR. Conclusão: Esses dados reforçam o caráter sistêmico da AR e levantam a necessidade de uma avaliação global do paciente, que não foque apenas no componente articular, mas verifique também a força dos músculos respiratórios desses indivíduos, para determinação de estratégias terapêuticas mais específicas e adequadas.

Maintaining Muscle Strength in Crohn’s Disease: Can a Vitamin D Daily Keep Muscle Loss Away?

Intact skeletal muscle strength and function are underappreciated aspects of normal human functioning. Moreover, it is widely accepted that muscle strength is a predictor of physical disability in patients with chronic diseases similar to inflammatory bowel disease (IBD, comprising Crohn’s disease and ulcerative colitis) such as rheumatoid arthritis [1], but also in normal ageing where healthy persons with a greater reserve in muscle function appear to have longer life spans [2]. Despite the intuitive importance of skeletal muscle in daily living, and the recent interest in the characterization of disability in patients with IBD [3], hitherto there are few studies examining muscle dysfunction in IBD [4]. In this issue, Salacinski et al. [5] have objectively demonstrated reduced lower limb muscle strength in subjects with Crohn’s disease (CD) compared to healthy controls, confirming the work of previous studies [6, 7]. However, the study was unable to show that this reduced strength was directly attributable to lower vitamin D (25(OH) or vitamin D3) levels in CD subjects as originally hypothesized. This exemplifies the complexity of teasing out potential causative and/or contributing factors in the reduced muscle strength and performance seen in CD. Delving Further into Vitamin D

Efecto del calcio y la vitamina D en la reducción de caídas de las personas mayores: ensayo clínico aleatorizado frente a placebo

Background and objectiveSupplements of calcium and vitamin D (Ca/VitD) could help prevent falls, although it is unknown whether the effect differs according to the level of physical activity or baseline 25-OH-vitamin D3. The objective is to determine the effect of Ca/VitD supplements in reducing falls and the musculoskeletal function in elderly over 65 years living in the community, who do not have osteoporosis or vitamin D deficiency. Material and methodRandomized double-blinded clinical trial. A total of 508 patients were selected from 35 Family Medicine consultations. The treatment was administered to 398 subjects (Ca/VitD 188 and placebo 210). The efficacy parameters were: incidence of falls, changes in muscle strength in dominant hand and changes in musculoskeletal function. ResultsThe cumulative incidence of falls in the group Ca/VitD was 27.7% (95% confidence interval [95% CI]: 21.0 to 34.3) and 30.5% in the placebo group (95% CI: 24.0 to 36.9) (P=.537). The difference was not significant in the subgroup analysis: male/female, active/inactive physically and level of 25-OH-vitamin D3 higher/less than 32ng/ml. There was no difference in muscle strength in subjects of both groups. The proportion of adverse effects was higher in the Ca/VitD group (14.4 versus 7.1%, P=.019). ConclusionsThe results contradict the recommendation to provide supplements, and it is not an effective and well tolerated strategy. Although they may reduce the risk of falls when there are very low levels of vitamin D, the results are unsatisfactory when elders do not have this deficiency, and it is necessary to consider the possibility of adverse effects.

An Assessment of Hamstring Flexibility of Subjects with Knee Osteoarthritis and Their Age Matched Control

Most often, attention is focused on management of pains, restricted joint motions and decreased muscle strength in subjects with knee osteoarthritis, with little attention on hamstring flexibility training. The objectives of this study were to assess and compare hamstring flexibility of subjects with knee osteoarthritis with their age matched healthy control. Forty-four subjects with grade III knee osteoarthritis and 58 apparently healthy individuals participated in the study. Hamstring flexibility, pain and knee flexion range of motion of both groups were measured. The data was analyzed using descriptive statistic and parametric inferential statistics [student t-test and Pearson’s product moment correlation]. The result showed that the mean flexibility of apparently healthy individual was significantly higher than that of subjects with knee osteoarthritis [t = 2.84, p<0.001]. Also, there was significant correlation between age, BMI, height and flexibility of the subjects with knee OA [r = -0.453, p = 0.002; r = -0.568 p = 0.034, r = 0.328, p = 0.030] respectively. This study concluded that the mean hamstring flexibility of subjects with knee osteoarthritis was significantly lower than that of apparently healthy individual.

Motor Imagery did not Improve Strength of Biceps Brachii

Numerous studies have confirmed that motor imagery may result in plastic change in motor system as actual physical activity. However, whether motor imagery can improve muscle strength of the trained persons remains unclear. The aim of this study is to investigate the effect of motor imagery on muscle strength. Totally 12 healthy college students were involved in 4 weeks of mental rehearsal of right upper limb movements (flexion and extension of elbow) during 30 min supervision session three times a week. Electromyogram (EMG) and peak torque of biceps brachii, reaction time of subjects were analyzed. Results showed that no significant change in EMG of biceps brachii was observed during motor imagery. After motor rehearsal for 4 weeks, statistically significant difference in EMG, peak torque and reactivity were not observed (P > 0.05) when compared with the baseline data. Therefore, motor imagery could not enhance muscle strength of subjects. Whether mental practice is a valid rehabilitation technique needs to be investigated further.

Effect of Eccentric Isotonic Quadriceps Muscle Exercises on Patellofemoral Pain Syndrome: An Exploratory Pilot Study

There is a decrease in quadriceps muscle strength in subjects with patellofemoral pain syndrome. Various types of strengthening exercises of the quadriceps are done as part of its management, but the effect of isotonic eccentric quadriceps muscle exercises on patellofemoral pain syndrome has not been studied. Hence the aim of this exploratory pilot study was to evaluate the effect of eccentric quadriceps training in patients with patellofemoral pain. Twenty patients (12 female and 8 male, mean ages, 27.50 +/- 6.6 years) with patellofemoral pain syndrome were treated. The eccentric training of the quadriceps was given using a Baltimore Therapeutic Equipment (BTE) Primus machine. The main outcome measures used were percentage time on target as shown by the BTE primus machine, SF-36 Health questionnaire and patellofemoral pain severity scale. Statistical analysis was performed using SPSS 13. All the outcome measures showed significant improvements (P<0.05). Percentage time on target improved with a mean difference of 23.6, the SF-36 questionnaire showed an improvement in physical component score, mental component score and bodily pain with a mean difference of 10.9, 2.6 and 29.2 respectively and pain score when taken using patellofemoral severity scale also improved with a mean difference of 3.4. Isotonic eccentric training of quadriceps muscles was found to be effective in reducing pain and improving the functional status of patients with patellofemoral pain syndrome and can be suggested as part of the treatment.

Evaluation of anthropometric parameters and physical fitness in elderly Japanese

We evaluated anthropometric parameters and physical fitness in elderly Japanese. A total of 2,106 elderly Japanese (749 men and 1,357 women), aged 60-79 years, were enrolled in a cross-sectional investigation study. Anthropometric parameters and physical fitness, i.e., muscle strength and flexibility, were measured. Of the 2,106 subjects, 569 subjects (302 men and 267 women) were further evaluated for aerobic exercise level, using the ventilatory threshold (VT). Muscle strength in subjects in their 70s was significantly lower than that in subjects in their 60s in both sexes. Two hundred and twenty-nine men (30.6%) and 540 women (39.8%) were taking no medications. In men, anthropometric parameters were significantly lower and muscle strength, flexibility, and work rate at VT were significantly higher in subjects without medications than these values in subjects with medications. In women, body weight, body mass index (BMI), and abdominal circumference were significantly lower, and muscle strength was significantly higher in subjects without medications than these values in subjects with medications. This mean value may provide a useful database for evaluating anthropometric parameters and physical fitness in elderly Japanese subjects.

The relationship between hamstring length and gluteal muscle strength in individuals with sacroiliac joint dysfunction

It has been suggested that tight hamstring muscle, due to its anatomical connections, could be a compensatory mechanism for providing sacroiliac (SI) joint stability in patients with gluteal muscle weakness and SIJ dysfunction. The purpose of this study was to determine the relationship between hamstring muscle length and gluteal muscle strength in subjects with sacroiliac joint dysfunction. A total of 159 subjects with and without low back pain (LBP) between the ages of 20 and 65 years participate in the study. Subjects were categorized into three groups: LBP without SIJ involvement (n = 53); back pain with SIJ dysfunction (n = 53); and no low back pain (n = 53). Hamstring muscle length and gluteal muscle strength were measured in all subjects. The number of individuals with gluteal weakness was significantly (P = 0·02) higher in subjects with SI joint dysfunction (66%) compared to those with LBP without SI joint dysfunctions (34%). In pooled data, there was no significant difference (P = 0·31) in hamstring muscle length between subjects with SI joint dysfunction and those with back pain without SI involvement. In subjects with SI joint dysfunction, however, those with gluteal muscle weakness had significantly (P = 0·02) shorter hamstring muscle length (mean = 158±11°) compared to individuals without gluteal weakness (mean = 165±10°). There was no statistically significant difference (P>0·05) in hamstring muscle length between individuals with and without gluteal muscle weakness in other groups. In conclusion, hamstring tightness in subjects with SI joint dysfunction could be related to gluteal muscle weakness. The slight difference in hamstring muscle length found in this study, although statistically significant, was not sufficient for making any definite conclusions. Further studies are needed to establish the role of hamstring muscle in SI joint stability.