Quadriceps Muscle Torque Research Articles

The Role of Cystic Fibrosis Transmembrane Conductance Regulator in Skeletal Muscle Contractile Function

Purpose: Genetic mutations in cystic fibrosis (CF) result in CF transmembrane conductance regulator (CFTR) dysfunction. CFTR is expressed in human skeletal muscle; its effect on skeletal muscle abnormalities is unknown. The study objective is to investigate the role of CFTR in skeletal muscle contractile function. Methods: We conducted a prospective, cross-sectional study comparing 34 adults with minimal and 18 with residual function CFTR mutations, recruited from Toronto Adult CF Centre, St. Michael's Hospital, Unity Health Toronto. Quadriceps, biceps brachii, and handgrip strength was measured with dynamometers; leg muscle power with the stair climb power test. Quadriceps muscle contractility was determined by quadriceps muscle strength normalized to quadriceps muscle size, measured with ultrasound images. Multivariable regression was used for analysis. Results: People with residual function CFTR mutations had higher quadriceps muscle torque normalized to quadriceps layer thickness and to rectus femoris cross-sectional area by 27.5 Nm/cm [95% CI (2.2, 52.8) Nm/cm, P = .034] and 5.6 Nm/cm2 [95% CI (0.3, 10.9) Nm/cm2, P = .041], respectively, compared with those with minimal function CFTR mutations. There were no differences in quadriceps muscle torque (P = .58), leg muscle power (P = .47), biceps brachii muscle force (P = .14), or handgrip force (P = .12) between the 2 mutation groups. Conclusions: CFTR protein may play a role in muscle contractility, implying a limited capacity to exert muscle force per unit of muscle size in people with CF. This suggests that building a greater muscle mass through resistance exercises focusing on muscle hypertrophy in exercise prescription may improve muscle strength in people with CF.

Comparison of the Dynamometer- and Kinematics-based Analyses for Measuring Individual Quadriceps Muscle Torque: A Pilot Study

Comparison of the Dynamometer- and Kinematics-based Analyses for Measuring Individual Quadriceps Muscle Torque: A Pilot Study

Immediate effects of kinesiology tape on quadriceps muscle peak torque and knee joint repositioning error in healthy males: Effects of different tensions and directions

BackgroundKnee joint injuries may result from compromised quadriceps muscle strength or diminished knee joint proprioception. The application of Kinesio tape (KT) on the quadriceps muscle from origin to insertion (OTI-KT) or insertion to origin (ITO-KT) could impact knee joint proprioception and quadriceps muscle strength. This study aims to assess the effects of different tensions and directions of KT application on active and passive knee joint repositioning errors (AJRE and PJRE) and peak concentric and eccentric peak torque (CPT and EPT) of the quadriceps muscles in healthy males. MethodTwenty-one healthy males participated in this repeated-measures study design. CPT, EPT, AJRE, and PJRE of the dominant limb were measured by a Biodex dynamometer before and after applying OTI-KT with 0%, 15%, and 40% extra tensions and ITO-KT with 0% tension. ResultsITO-KT demonstrated a significant reduction in AJRE (p < 0.05). Meanwhile, for OTI-KT, a statistically significant difference was observed in both AJRE and PJRE concerning time (F1,126 = 19.74, p < 0.05 for AJRE; F1,126 = 9.96, p < 0.05 for PJRE) and tension (F2,126 = 22.14, p < 0.05 for AJRE; F2,126 = 20.67, p < 0.05 for PJRE). ConclusionApplying KT, especially OTI KT with 40% and 15% extra tension, shows potential in enhancing knee proprioception without immediate impacts on quadriceps muscle torque. This suggests applications in sports performance and knee injury rehabilitation.

Interpretation of Normative Score of Hamstring and Quadriceps Isokinetic Peak Torque among University Students: A Pilot Study

Introduction: Understanding normative scores can help in identifying individuals who may be at risk of injury due to muscle imbalances or weakness. By comparing an individual’s scores to the normal, interventions can be implemented to address any deficits and reduce the risk of injuries, particularly in physically active populations like college students involved in sports or physical activities. Aim: To evaluate the normative reference score of isokinetic peak torque of hamstring and quadriceps muscles among healthy college-going students from the age group 18-25 years. Materials and Methods: This pilot study was conducted in the Department of Physiotherapy, Maharishi Markandeshwar Institute of Physiotherapy and Rehabilitation, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala, Haryana, India and enrolled 50 healthy college-going students. Permission was taken from participants in the Institutional Research Laboratory for data collection. Students aged 18 to 25 years were enlisted for the research. All participants were sensitised about the procedure before they participated in the study. The participants were provided consent form. Results: The normative reference value of RHq_R was mean±SD 1.18±0.61, median (IQR) was 1.07(0.76, 1.43), skewness was 1.26, kurtosis was 1.37 and for the LHq_L mean±SD was 1.35± 0.71, median {Interquartile Range (IQL)} was 1.21(0.83, 1.80) and the skewness, kurtosis was 1.18 and 0.97, respectively. Conclusion: The study found that college students had weak quadriceps and hamstring strength. It also revealed that these students had a bad Hamstring:Quadriceps strength (H:Q) ratio and were more likely to have hamstring injuries.

Peak Quadriceps Muscle Torque and Electromyographic Output in Patients With Chronic Respiratory Disorders: Effects of Pulmonary Rehabilitation

ObjectiveTo assess the change in relation of the peak quadriceps electromyographic signal to the peak torque produced during a train of 5 isokinetic knee extensions (from 90 degrees below horizontal at a constant speed of 60 degrees/s) at baseline, and at 4 and 8 weeks of pulmonary rehabilitation. DesignIn this prospective observational study, isokinetic contractions were recorded during the extensions from the knee bent at 90 degrees to the horizontal plane against graded resistance. Peak quadriceps torque signal (Tq) and peak electromyographic signal (Eq) were recorded by dynamometry and surface electrodes placed at designated locations over the muscle group, respectively. SettingPhysical therapy department in a tertiary care medical center. ParticipantsEighteen patients (9 restrictive lung disease, 6 chronic airflow limitation, 3 non-ILD restrictive; N=18) were compared with 11 healthy control subjects. InterventionsPatients underwent an 8-week pulmonary rehabilitation program. Main Outcome MeasuresComparisons of Tq, Eq, and Tq/Eq ratio among patients and controls were by analysis of variance. Associations between physiological variables were determined by multivariable Pearson's correlation. ResultsCompared with patients, controls exhibited a 22% higher baseline mean peak Eq (P<.05) and 76% higher mean peak Tq (P=.02) during knee extensions. Patients’ peak Eq/Tq was twice as high as in the controls (P=.02); at 4 weeks, Eq/Tq in patients decreased by 44% (P<.04) with no further decline at 8 weeks; changes in Eq/Tq of 5 of 6 patients paralleled changes in their respective St George's Respiratory Questionnaire scores. There was no change in Tq or Eq/Tq over time among the control cohort. ConclusionsEight weeks of pulmonary rehabilitation result in a decrease in Eq/Tq, indicating improvement in force generation of limb muscles, with the change occurring in the first 4 weeks.

Association Between Protocols of the Sit-to-Stand Test and Lower Limb Muscle Force Output in Patients on Hemodialysis and Subjects Without Chronic Kidney Disease

To evaluate the association of three protocols of the sit-to-stand (STS) test with muscle force output of knee extension (KE) and knee flexion (KF) in patients on hemodialysis and subjects without chronic kidney disease. This cross-sectional study included a hemodialysis group [n=60, 59.5 (16.8) years, 55% female] and a control group [n=60, 43.0 (11.8) years, 50% female]. The assessments were performed in 2days, and the participants were submitted to three protocols of STS test (5-repetition STS, 10-repetition STS and 30-s STS) or muscle force output of the KE and KF evaluation by handheld dynamometer based on randomization. The hemodialysis group presented reduced muscle force output of the KE and KF, a longer time to perform the 5 STS and 10 STS tests, and a lower number of repetitions in the 30-s STS test. The three STS tests were associated with muscle force output of the KE in the hemodialysis group, in which the 10-repetition STS test showed the best association (R2=0.47; adjusted R2=0.42). However, the only association between the STS test and muscle force output of the KE in the control group was found in the 10-repetition STS test (R2=0.20; adjusted R2=0.13). The three protocols of STS tests were associated with muscle force output of the KE in patients on hemodialysis. However, the 10-repetition STS test was the best protocol to estimate the quadriceps muscle torque in these patients.

Effect of soft tissue manipulation of popliteus muscle on quadriceps muscle activity and torque production in athletes with anterior knee pain

Abstract Study aim: Popliteus is majorly associated with posterior knee pain; however, this muscle can also have an impact on anterior knee pain. The purpose of this study was to determine the effect of soft tissue manipulation of popliteus muscle on non-traumatic anterior knee pain in athletes; as the relationship between popliteus and Quadriceps muscle has not been studied/explored much. Materials and methods: In this experimental study, 15 subjects presenting with non-traumatic anterior knee pain were selected. Quadriceps muscle activity, torque production and knee pain were assessed. Followed by a single session of popliteus manipulation all the above parameters were re-assessed immediately and at 24 hours after intervention. Results: Significant reduction in pain (P &lt; 0.005) at 24 hours was observed. There was a significant increase in muscle activity of Vastus Medialis (P &lt; 0.05) and Vastus Lateralis (P &lt; 0.005) immediately after the intervention but not after 24 hours. No significant change was found in the activity of Rectus femoris and Peak torque of Quadriceps immediately after the intervention and at 24 hours. Conclusion: Soft tissue manipulation decreased knee pain and improved muscle activity. Therefore, incorporating popliteus manipulation can be effective in treatment of anterior knee pain.

Low-energy laser therapy application on knee joints as an auxiliary treatment in patients with polyarticular juvenile idiopathic arthritis: a dual-arm randomized clinical trial.

Patients with juvenile idiopathic arthritis (JIA) always experience persistent pain and stiffness which induces muscle weakness, fatigue, and functional limitations. This study evaluated whether applying low-energy laser therapy (LLT) on the knee joint could be an effective adjuvant intervention for patients with JIA. Sixty children with polyarticular JIA participated and were randomly allocated to receive either LLT (wavelength λ = 903nm; power output of 50 mW; and energy of 1.5J) plus exercises (LLT group) or exercises alone (control group). Pain, peak concentric torque of quadriceps muscles, fatigue, and functional status were measured by the visual analogue scale, isokinetic testing system, Pediatric Quality of Life Inventory Multidimensional Fatigue Scale, and Childhood Health Assessment Questionnaire, respectively pre- and post-intervention, and at 6-month follow-up. Per the mixed-model analysis of variance, the LLT group showed a statistically more favorable improvement in pain (P = .003, ηp2 = .014), fatigue perception (P = .004, ηp2 = .015), and functional status (P = .022, ηp2 = .09) across the three assessment occasions, as compared to the control group. However, no significant difference was demonstrated between both groups concerning peak concentric torque (all P > .05). Incorporation of LLT into the standard physical rehabilitation program for patients with JIA has the potential to induce more conducive improvements in pain, fatigue, and functional performance, but is not effective for improving muscle performance.

Effects of neuromuscular electrical stimulation on torque and performance in recreational distance runners: A randomized controlled trial

IntroductionNeuromuscular electrical stimulation (NMES) is used by athletes to improve muscle performance. However, evidence on the use of NMES in long distance runners is scarce. As such, this study aimed to evaluate the effects of NMES on the muscle torque and sports performance of long-distance recreational runners. MethodsThis was a blinded randomized controlled trial. Data from 30 volunteers were analyzed. Participants were randomly allocated to an experimental (n = 15) or control group (n = 15). The experimental group was submitted to running training (RT) and a strengthening protocol with NMES (1 kHz, modulated in 2 ms bursts, 50 Hz modulated burst frequency and 10% duty cycle, 15 min totaling 18 contractions per sessions) for 6 weeks, with 3 sessions per week, while controls were submitted to RT alone. The following variables were analyzed: peak isometric (ISO), concentric (CON), and eccentric (ECC) torque of the quadriceps muscle in voluntary contractions, ventilatory anaerobic thresholds (VATs), maximal oxygen uptake (VO2max), and oxygen cost of transport (OCT). ResultsThe NMES group obtained higher values of ISO, 21.04% (p = 0.001), CON, 21.97% (p = 0.001) and ECC, 18.74% (p = 0.001) peak torque and VAT1, 9.56% (p = 0.001), as well as a statistically significant improvement in oxygen cost of transport at VAT1 when compared to controls (p = 0.001). ConclusionNMES was effective in improving peak isometric, concentric and eccentric quadriceps muscle torque, in addition to being an interesting resource for enhancing sports performance in long-distance recreational runners and future clinical trials should be performed to compare the use of NMES to different forms of training over longer training periods.

Does the Direction of Kinesiology Tape Application Influence Muscle Activation in Asymptomatic Individuals?

BackgroundDespite the popularity of tape among athletes and rehabilitation practitioners, there is controversy regarding the specific effects of kinesiology tape. Based on conflicting results and limitations of the literature, a well-designed study was desired to examine kinesiology tape application direction on muscle activation.Hypothesis/PurposeThe purpose of this pilot study was to determine if the direction of kinesiology tape application influences quadriceps activation. This study compared taping techniques with outcome measures selected to assess quadriceps muscle activation. The outcome measures included EMG, isokinetic strength, and functional hop and jump performance.Study DesignDouble-blind Crossover studyMethodsA total of fifteen asymptomatic participants (10 females and 5 males) completed the study. Mean age was 23.3 years. KinesioⓇ Tex GoldTM was applied to the dominant lower extremity of each participant using a Y-strip method. Two taping conditions (proximal to distal, distal to proximal) were applied to the quadriceps. Participants and testers were blinded to tape condition. Pretest and posttest measures included electromyographic output during isokinetic testing of quadriceps muscle torque at 60°s-1 and 120°s-1, single leg triple hop for distance, and vertical jump.ResultsTwo-way, repeated measures analysis of variance resulted in no significant differences in baseline to taped condition for quadriceps electromyographic output, quadriceps isokinetic knee extension muscle torque at 60°s-1 and 120°s-1, single leg triple-hop distance or vertical jump height.ConclusionThe results of this pilot study do not support the hypothesis that kinesiology tape application direction influences muscle performance as measured in this study.Levels of EvidenceLevel 1 – Controlled Clinical TrialClinical RelevanceKinesiology tape is commonly used as an intervention for a wide range of musculoskeletal conditions and for promoting performance including sporting activities. Kinesiology tape is popular among athletes and health care providers yet the specific effects of tape are not well understood.

Dose-Response Relationship Between Neuromuscular Electrical Stimulation and Muscle Function in People With Rheumatoid Arthritis.

Neuromuscular electrical stimulation (NMES) is a viable intervention for improving impaired muscle function in individuals with rheumatoid arthritis (RA). However, there is limited evidence about the dose-response relationship between NMES and muscle function in these individuals. The objectives of this study were to investigate the dose-response relationship between NMES and muscle function in individuals with RA and to establish the minimal NMES training intensity for promoting improvements. This study was a secondary analysis of data obtained before and after an NMES intervention in a randomized study. The study took place at a research clinic. Only adults diagnosed with RA were included. The intervention consisted of 36 NMES treatment sessions for the quadriceps muscles over 16 weeks. Muscle function was measured before and after the intervention; quadriceps cross-sectional area and muscle quality were assessed using computed tomography, and strength was measured with an isokinetic dynamometer. NMES training intensity was calculated as a percentage by dividing NMES-elicited quadriceps muscle torque by the maximum voluntary isometric contraction. Improvements in muscle function were calculated using paired-sample t tests. The dose-response relationship was determined using curve estimation regression statistics. The minimum NMES training intensity was defined as that sufficient to significantly improve all muscle function measures. Twenty-four people (48 legs) participated (75% women; mean [SD] age = 58 [8] years; mean body mass index=32 [7] kg/m2). Quadriceps cross-sectional area, muscle quality, and strength improved after the intervention. Associations between NMES training intensity and muscle quality (r2=0.20) and strength (r2=0.23) were statistically significant, but that between NMES training intensity and muscle cross-sectional area was not (r2=0.02). The minimum NMES training intensity necessary to improve all measures of muscle function ranged from 11% to 20% of the maximum voluntary isometric contraction. The relatively small sample size was a limitation. The minimum NMES training intensity for significant gains in muscle function was ∼15%. Higher NMES intensities may promote better muscle quality and strength in individuals with RA.

Effects of inclined treadmill training on functional and cardiovascular parameters of stroke patients: study protocol for a randomized controlled trial

BackgroundTreadmill training has been widely used for gait recovery after stroke. Gait re-establishment is one of the main objectives of rehabilitation programs after stroke, aiming to acquire more functional patterns and increase walking speed, along with improvement in cardiovascular function. The aim of this study is to evaluate the effects of a treadmill gait training protocol on functional and cardiovascular variables in patients with chronic stroke.MethodsA single-blind randomized clinical trial will be conducted. The sample will consist of 36 patients, who will be allocated in three groups: control group (n = 12), experimental group 1 (n = 12), and experimental group 2 (n = 12). The intervention will occur for 6 consecutive weeks, three times a week, 30 min each session, in all groups. The control group will perform a treadmill gait training without inclination, experimental group 1 will perform a treadmill gait training with anterior inclination of 5%, and experimental group 2 will perform a treadmill gait training with anterior inclination of 10%. All participants will be assessed for sample characterization measures, gait speed, functional capacity, systemic arterial blood pressure, heart rate, peripheral oxygen saturation, exercise capacity, neuromuscular torque, and quality of life. Evaluations of outcome measures will occur at the end of the interventions (post-training) and after 1 month and 1 year after the end of the interventions (short- and long-term follow-up). Statistical analysis will be performed descriptively and inferentially. Alpha equals 5% will be considered for inferential analysis. Mixed analysis of variance with repeated measures will be used to compare outcome measures between groups and between baseline, post-training, and follow-up. Normality test (Shapiro–Wilk) and subsequently t test (or Mann–Whitney) will be used to compare groups during the same training session.DiscussionIt is believed that treadmill training, especially treadmill training with anterior inclination, may result in improved exercise capacity in patients with stroke, reduced blood pressure and heart rate values, and an improvement in functional parameters with increased gait speed, functional capacity, quadriceps muscle torque, and quality of life.Trial registrationRegistration in Brazilian Registry of Clinical Trials (ReBEC) identifier RBR-5ffbxz, date of registration October 25 2017.

Interpretation of isokinetic peak torque of hamstring and quadriceps muscles and its correlation with the flexibility of these muscles in Saudi- adolescent males

Interpretation of isokinetic peak torque of hamstring and quadriceps muscles and its correlation with the flexibility of these muscles in Saudi- adolescent males

Dependence of Muscle Torque of Ankle Plantar and Dorsal Flexors on Different Ankle Angles

Research background and hypothesis. There is much research information about the relationship between the knee joint angle and the quadriceps muscle torque (Mohamed et al., 2002), but still we lack evidence about the relationship between ankle angle and calf muscle torque. Research aim. The purpose of this research was to establish the dependence of maximal voluntary contraction (MVC) and electrical stimulation (ES)-evoked torque and calf muscle electrical activity (EMG) on different ankle plantar and dorsal fl exion angles. We hypothesized that the calf muscle MVC and ES-evoked torque as well as muscle EMG amplitude would increase with increasing muscle length (i. . increasing ankle angle).Research methods. The subjects in the research were ten non-trained men. Calf plantar and dorsal fl exors muscle ES and MVC torque were tested at eight different ankle angles (–25 o ; –15 o ; –5 o ; 0 o ; 15 o ; 25 o ; 35 o ; 45 o ) which were chosen in randomized sequence. The tibialis anterior, soleus, gastrocnemius lateralis and medialis muscle EMG were measured during muscle MVC.Research results. The results showed that the highest ES-evoked and MVC developed torque of plantar fl exion muscles was at –25° ankle angle (149.1 ± 31.6 N·m and 207.8 ± 38.1 N·m, respectively), while the highest dorsal fl exion MVC muscle torque was at 25° ankle angle (47.2 ± 8.1 N·m). However, dorsal fl exion muscle MVC torque increased with the muscle length only until 25° ankle angle. Discussion and conclusions. Plantar flexion muscle electrical stimulation evoked and plantar / dorsal fl exion muscle maximal voluntary contraction torques are highest at that ankle angle where muscle length is the longest.Keywords: maximal voluntary contraction, electrical stimulation, EMG.

Knee Muscle Torque and H:Q Ratio Changes before ACL Surgery and after Rehabilitation

Research background and hypothesis. Anterior cruciate ligament (ACL) of the knee joint is often quite a fragile structure of the knee. After the rupture of ACL neuromuscular control worsens and sensorimotor system breaks down (Risberg et al., 2007), muscle activation is poor and muscle strength decreases (Croce, Miller, 2006). Some authors have reported greater strength loss in quadriceps femoris than in hamstring femoris muscle (Busch-Joseph et al., 2001; Neeter et al., 2006), therefore we hypothesized that strength loss in knee extensors may affect hamstring/quadriceps torque (H:Q) ratio. Research aim of this study was to investigate knee extensors and fl exors isometric and dynamic torque and H:Q ratio alterations before ACL surgery and after rehabilitation.Research methods. Ten volunteers with ACL ruptured knee where tested before surgery and after rehabilitation. Isokinetic dynamometer was used for this testing. Maximal isometric torque was performed during fl exion and extension at 90°, 60º knee angles. Dynamic torque was performed at 30, 180, 300º/s angular velocities.Research results. Results of this study show that after rehabilitation isometric and dynamic torque of the involved leg decreased. Isometric fl exion and extension torque of the uninjured leg was greater than that of the injured leg, but after rehabilitation the extension torque of the injured leg was lower than that before surgery. Discussion and conclusions. Before ACL surgery and after rehabilitation quadriceps femoris muscle torque of the uninjured leg was more affected than hamstring femoris muscle torque. After rehabilitation H:Q ratio of the injured leg was not dependent on angular velocity and knee joint angle.Keywords: maximal voluntary torque, muscle balance, muscle contraction.

Quadriceps Rate of Torque Development and Disability in Persons With Tibiofemoral Osteoarthritis.

Background Declines in the ability to rapidly generate quadriceps muscle torque may underlie disability in individuals with tibiofemoral osteoarthritis. Objective To determine whether quadriceps rate of torque development (RTD) predicts self-reported disability and physical performance outcomes in individuals with tibiofemoral osteoarthritis. Methods This controlled laboratory, cross-sectional study assessed quadriceps strength and RTD in 76 individuals (55% female; mean ± SD age, 61.83 ± 7.11 years) with symptomatic and radiographic tibiofemoral osteoarthritis. Early (0-50 milliseconds), late (100-200 milliseconds), and overall peak RTDs were quantified in the symptomatic (involved) and contralateral limbs and used to calculate bilateral average values. Disability was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function subscale and 3 physical performance tests, including the (1) 20-m fast-paced walk, (2) 30-second chair stand, and (3) timed stair climb. Separate univariate regression models were used to determine the unique associations among measures of quadriceps RTD, WOMAC function score, and physical performance outcomes after accounting for quadriceps strength (change in R2). Results Greater involved-side late RTD and greater bilateral average early RTD were associated with faster walking (change in R2 = 0.05, P = .013 and change in R2 = 0.05, P = .043, respectively). Greater bilateral average late RTD was associated with faster walking (change in R2 = 0.20, P<.001) and faster stair climb (change in R2 = 0.11, P = .001). No quadriceps RTD variable was significantly associated with WOMAC function score (change in R2 range, <0.01-0.017). Conclusion Involved-limb quadriceps RTD was weakly associated with physical performance outcomes, but not self-reported disability, in individuals with tibiofemoral osteoarthritis. Bilateral average quadriceps RTD was moderately associated with walking speed. Level of Evidence Prognosis, level 2b. J Orthop Sports Phys Ther 2018;48(9):694-703. Epub 22 May 2018. doi:10.2519/jospt.2018.7898.

A 6-week hip muscle strengthening and lumbopelvic-hip core stabilization program to improve pain, function, and quality of life in persons with patellofemoral osteoarthritis: a feasibility pilot study

BackgroundPatellofemoral joint (PFJ) osteoarthritis (OA) is prevalent in middle-aged and older adults. Despite this, there are minimal studies which have examined conservative interventions for PFJ OA. Weakness of proximal lower extremity muscles is associated with PFJ OA. It is unknown if a hip muscle strengthening and lumbopelvic-hip core stabilization program will improve symptoms and function in persons with PFJ OA. This study examined the feasibility and impact of a 6-week hip muscle strengthening and core stabilization program on pain, symptoms, physical performance, peak muscle torques, and quality of life in persons with PFJ OA.MethodsTen females with PFJ OA and ten age- and sex-matched controls participated in baseline tests. PFJ OA participants attended ten twice-a-week hip strengthening and core stabilization exercise sessions. Outcome measures included questionnaires, the Timed-Up-and-Go, and peak isometric torque of hip and quadriceps muscles. Data were tested for normality; parametric and non-parametric tests were used as appropriate.ResultsAt baseline, the PFJ OA group had significantly worse symptoms, slower Timed-Up-and-Go performance, and lower muscle torques than control participants. PFJ OA group adherence to supervised exercise sessions was adequate. All PFJ OA participants attended at least nine exercise sessions. Five PFJ OA participants returned 6-month follow-up questionnaires, which was considered fair retention. The PFJ OA participants’ self-reported pain, symptoms, function in daily living, function in sport, and quality of life all improved at 6 weeks (P < 0.05). Timed-Up-and-Go time score improved at 6 weeks (P = 0.005). Peak hip external rotator torque increased (P = 0.01). Improvements in pain and self-reported function were no longer significant 6 months following completion of the intervention.ConclusionsPFJ OA participants were adherent to the supervised sessions of the intervention. Improvement in symptoms, physical performance, and muscle torque were found after 6 weeks. Participant retention at 6 months was fair, and significant changes were no longer present. Our findings suggest that a hip strengthening and core stabilization program may be beneficial to improve symptoms, function, and physical performance in persons with PFJ OA. Future studies are needed, and additional measures should be taken to improve long-term adherence to exercise.Trial registrationClinicalTrials.gov NCT02825238. Registered 6 July 2016 (retrospectively registered).

Reliability and validity of the five-repetition sit-to-stand test in adult kidney transplant recipients

Background/Aims: To investigate the reliability and validity of the five-repetition sit-to-stand test (FRSTST) to assess lower-limb muscle strength and physical function in adult kidney transplant recipients. Methods: A cross-sectional, observational study was conducted in a secondary care centre. A convenience sample of 56 adult kidney transplant recipients were recruited following a 6-week post-transplantation recovery period. The participants were within their first 18 months of kidney transplantation. The measurements included FRSTST times, myometer measurements of isometric quadriceps muscle strength, 60-second sit-to-stand test (STS60) scores, and Duke Activity Status Index (DASI) scores. Findings: Inter- and intratester reliability of the FRSTST were excellent (intraclass correlation coefficients 0.997 and 0.970, respectively). The standard error of measurement and the minimal detectable change at 95% confidence level were 0.9 and 2.5 seconds, respectively. The best FRSTST scores by the two testers had non-significant, weak correlations with the isometric quadriceps muscle force (Spearman's rho, rs=-0.04, p=0.76), and quadriceps muscle torque (rs=0.04, p=0.76). The FRSTST correlated significantly with the STS60 (rs=-0.90, p=0.001) and DASI scores (rs=-0.49, p=0.001). Conclusions: The FRSTST can be considered to be a reliable test of physical function for adult kidney transplant recipients, but may not be used as a surrogate measure of lower limb muscle strength in this population.

Effect of Pulsed Magnetic Field on Peak Torque of Quadriceps/Hamstring Muscles and Knee Proprioception in Athletic Subjects:A Randomized Controlled Study

Background: Many therapeutic uses for Pulsed magnetic fields have been extensively studied. Beneficial effects on the musculoskeletal system were established including bone healing, pain relief, and inflammatory conditions. The study aimed at investigating the possible effects of the pulsed magnetic field on quadriceps muscle torque, hamstring muscle torque and knee proprioception accuracy in athletic subjects.Methods: A randomized controlled trial which was carried out at the Faculty of Medical Rehabilitation Sciences, Taibah University, Saudi Arabia. Thirty healthy male athletic subjects, aging from 18 – 24 years were divided into two groups, study group (15 subjects) &amp; control group (15 subjects). The pulsed magnetic field was applied for subjects of intervention group, while control group participants received sham pulsed magnetic field for 12 sessions over a period of 4 weeks. Quadriceps muscle torque, hamstring muscle torque &amp; knee proprioception accuracy were measured before &amp; after treatment for all participants using Biodex system 4 pro isokinetic dynamometer.Results: Multiway ANOVA was carried out to detect any significant differences within and between groups. Statistically significant differences between study and control groups were found after pulsed magnetic field application in quadriceps peak torque (at 60 and 120deg/sec) &amp; hamstring peak torque (at 60 and 120deg/sec) and in knee proprioception accuracy (p-value was 0.004, 0.0001, 0.02, 0.03, 0.0001 respectively).Conclusion: Pulsed magnetic field has beneficial effects on quadriceps muscle peak torque, hamstring muscle peak torque and knee proprioception accuracy in healthy athletic subjects and can be advised as an adjunctive tool in rehabilitation programs.

A comparison of isokinetic knee strength and power output ratios between female basketball and volleyball players

PurposeTests such as the counter movement jump (CMJ) and squat jump (SJ) allow for determining the ratio of maximal power output generated during SJ to CMJ (S/C). The isokinetic peak torque ratio of the hamstrings contracting eccentrically to the quadriceps contracting concentrically (H/Q) is defined as functional H/Q. The purpose of this study was to compare the S/C and functional H/Q between female basketball and volleyball players.MethodsThe total of 14 female basketball players (age, 19.8 ± 1.4 years) and 12 female volleyball players (age, 22.3 ± 4.2 years) participated in the study. A piezoelectric force platform was used for the CMJ and SJ. Moreover, isokinetic tests of the hamstrings and quadriceps muscle torque during eccentric and concentric contraction were performed.ResultsThe results of the S/C and functional H/Q at 90 deg • s&lt;sup&gt;–1&lt;/sup&gt;/60 deg • s&lt;sup&gt;–1&lt;/sup&gt; velocities were higher in basketball players (87.3 ± 9.1% and 91.4 ± 9.3%, respectively) than in volleyball players (83.1 ± 9.8% and 83.6 ± 16.5%, respectively). No significant differences in S/C or functional H/Q values between the two groups were found (&lt;i&gt;p&lt;/i&gt; &gt; 0.05).ConclusionsDecreasing the S/C may result from an improvement in the power output during CMJ and a better utilization of the stretch-shortening cycle effect. Balancing the functional H/Q through increasing the eccentric hamstrings strength can provide dynamic knee joint stabilization.