Instrument assisted soft tissue mobilization (IASTM) versus stretching: A comparison in effectiveness on hip active range of motion,muscle torque and power in people with hamstring tightness

BackgroundInstrument-assisted soft tissue mobilization (IASTM) is a new technique that has been known to be effective in reducing muscle tightness in athletics. However, little is known about its effect on the range of motion, muscle power, and torque compared to manual stretching among non-athletics. Thus, the study was aimed to compare the effectiveness between IASTM and manual stretching in improving hip flexion active range of motion (ROM), muscle torque and power on hamstring muscle complex (HMC) tightness in one session.MethodTwenty-three young male college students with unilateral hamstring tightness measured via straight leg raising (SLR) test (<65°) were randomly assigned to one of two groups. Twelve participants received the application of IASTM (group 1), and eleven received manual stretching (group 2). Hip flexion active ROM was measured via goniometer, the torque & power of the hamstring muscle were measured using Humac isokinetic dynamometer, before and after both interventions. (ISRCTN17693345).ResultsThere was no significant difference in the improvement of hip flexion active ROM (69.6 ± 6.6 vs 72.5 ± 7.9, p = .34), HMC torque (63.7 ± 14.5 vs 53.2 ± 16.3, p = .14), and HMC power (47.8 ± 11.8 vs 40.9 ± 16.3, p = .34) between group 1 and group 2 respectively. When a comparison was made within each group, significant improvements in hip active flexion ROM was found in both groups (p's < .001), and HMC power was significantly improved in group 1 (p = .04) but not in group 2.ConclusionThe current study findings demonstrate that IASTM was as effective as manual stretching in improving hip flexion active ROM, muscle torque and power among non-athletic people with HMC tightness.     

Effect of ankle dorsiflexion on displacement and strain in the tibial nerve and biceps femoris muscle at the posterior knee during the straight leg raise: Investigation of specificity of nerve movement

BackgroundA structural differentiation maneuver has been proposed to differentiate between muscle and nerve involvement during the straight leg raise test. However, to date, the mechanical specificity of this maneuver for the tibial nerve at the posterior knee has not been tested. The aim of this study was to investigate the specificity of ankle dorsiflexion as a differentiation maneuver between the tibial nerve and the biceps femoris muscle at the posterior knee during the straight leg raise in cadavers.MethodsA cross-sectional study was carried out. In fresh frozen cadavers, with microstrain devices and Vernier calipers, strain and excursion in the tibial nerve and distal biceps femoris muscle were measured during ankle dorsiflexion at 0°, 30°, 60° and 90° of hip flexion of the straight leg raise.FindingsAnkle dorsiflexion resulted in significant distal excursion and increased strain in the tibial nerve (p < 0.05) whilst the muscle was not affected by the dorsiflexion (p > 0.05) at all hip flexion angles.InterpretationAnkle dorsiflexion was mechanically specific between the tibial nerve and biceps femoris during the straight leg raise. This study adds to evidence that, in certain circumstances, dorsiflexion may be used in differentiation of nerve and muscle disorders in the posterior knee.     

Relationship between vertical ground reaction force and muscle strength while climbing stairs after total hip arthroplasty

BackgroundLittle is known about the relationship between vertical ground reaction force (vGRF) and muscle strength while climbing stairs after total hip arthroplasty (THA).MethodsWe investigated the relationship between muscle strength and vGRF during stair climbing in 21 women with THA. Differences in the time required to climb stairs and side-to-side differences in muscle strength and vGRF during climbing were examined at 6 and 12 months.The relationship between climbing time and vGRF variables and that between vGRF and muscle strength were analyzed using Spearman's rank correlation coefficient at 6 and 12 months. First peak force (Fz1) was defined as the peak vGRF at heel strike normalized by body weight.FindingsClimbing time was related to the time to Fz1 at 6 and 12 months post-THA (r = 0.50–0.64). At 6 months, time to Fz1 was related to the strength of muscles involved in hip extension in the operated limb (r = −0.46). At 12 months, time to Fz1 was related to the strength of muscles responsible for knee extension in the operated limb (r = −0.45).InterpretationAt 6 months, climbing stairs depended on muscle strength in the hip extensors. Conversely, at 12 months, the functional recovery of knee extensors was important for transferring weight upward while climbing stairs. Therefore, to improve the climbing function of patients with THA, it is important to not only focus on the recovery of muscle strength in the hip extensors but also improve muscle strength in the knee extensors.     

Trunk and lower limb biomechanics during stair climbing in people with and without symptomatic femoroacetabular impingement

BackgroundFemoroacetabular impingement is a pathomechanical hip condition leading to pain and impaired physical function. It has been shown that those with femoroacetabular impingement exhibit altered gait characteristics during level walking and stair climbing, and decreased muscle force production during isometric muscle contractions. However, no studies to-date have looked at trunk kinematics or muscle activation during dynamic movements such as stair climbing in this patient population. The purpose of this study was to compare biomechanical outcomes (trunk and lower limb kinematics as well as lower limb kinetics and muscle activation) during stair climbing in those with and without symptomatic femoroacetabular impingement.MethodsTrunk, hip, knee and ankle kinematics, as well as hip, knee and ankle kinetics and muscle activity of nine lower limb muscles were collected during stair climbing for 20 people with clinical and radiographic femoroacetabular impingement and compared to 20 age- and sex-matched pain-free individuals.FindingsThose with femoroacetabular impingement ascended the stairs slower (effect size = 0.82), had significantly increased peak trunk forward flexion angles (effect size = 0.99) and external hip flexion moments (effect size = 0.94) and had decreased peak external knee flexion moments (effect size = 0.90) compared to the control group.InterpretationFindings from this study indicate that while those with and without femoroacetabular impingement exhibit many biomechanical similarities when ascending stairs, differences in trunk forward flexion and joint kinetics indicate some important differences. Further longitudinal research is required to elucidate the cause of these differences as well as the clinical relevance.     

Activation of the gluteus maximus,gluteus medius and tensor fascia lata muscles during hip internal and external rotation exercises at three hip flexion postures

BackgroundHip internal and external rotation exercises are usually performed in clinical practice. However, given the synergies required to stabilize the hip in the frontal plane, it is not clear how the activation of target muscles will differ between the two exercise directions.ObjectiveI) Compare the activation of the upper and lower fibers of gluteus maximus (GMax), gluteus medius (GMed) and tensor fascia lata muscles between the hip internal and external rotation exercises; ii) Compare the maximal isometric force between hip internal and external rotation exercises and; iii) Assess the effect of varying hip flexion angles on muscle activation and maximal isometric force.Study designA cross sectional study.MethodsElectromyography and force production of twenty-one participants were measured during maximum isometric hip internal and external rotation in three postures: 0°, 45° and 90° of hip flexion.ResultsMANOVA results showed a larger activation of the GMed, tensor fascia lata and upper GMax (p < .001) for hip internal rotation compared to external rotation regardless of hip flexion angle. For the lower GMax, the same was observed when the hip was kept at 90° of flexion. Maximal isometric force during hip external rotation was greater than during hip internal rotation at 0° posture, and lower at 90° posture (p < .001).ConclusionThe gluteus and the tensor fascia lata muscles were substantially recruited during the hip internal rotation exercise, and barely recruited during the hip external rotation exercise. Hip flexion influences the myoeletric activity and isometric force production during the internal rotation exercise.     

Lower limb kinematics and hip extensors strengths are associated with performance of runners at high risk of injury during the modified Star Excursion Balance Test

BackgroundReduced trunk and lower limb movement and hip and trunk muscles weakness may compromise the athletes’ performance on the modified Star Excursion Balance Test (mSEBT).ObjectiveTo investigate the relationship of trunk and lower limb kinematics and strength with the performance on the mSEBT of runners at high risk of injury.MethodsThirty-nine runners performed the mSEBT with the dominant limb as the support limb. An Inertial System was used to capture the trunk, hip, knee and ankle movement during the mSEBT. A handheld dynamometer was used to measure the strength of trunk extensors and lateral flexors muscles, and hip extensors, lateral rotators and abductors of the support limb. Multiple regressions were used to investigate if trunk and lower limbs kinematics and trunk and hip muscles strength are associated with performance during the mSEBT.ResultsReduced hip flexion and greater knee flexion range of motion (ROM) were associated with anterior reach in the mSEBT (r² = 0.45; p < .001), greater hip flexion ROM was associated with posteromedial reach (r² = 0.15; p = .012) and greater knee flexion ROM was associated with posterolateral reach (r² = 0.23; p < .001). Hip extensor strength was associated with posteromedial (r² = 0.14; p = .017), posterolateral (r² = 0.10; p = .038) and composite reaches (r² = 0.16; p = .009).ConclusionHip and knee kinematics in the sagittal plane explained 15–45% of the runners’ performance on the mSEBT and hip extensor strength explained 10–16% of the mSEBT performance. These findings provide useful information on the contribution of joints kinematics and strength when evaluating dynamic postural control in runners at high risk of injury.     

Effect of increased relative stiffness of the lumbar spine on hamstring muscle stretching in individuals with a history of low back pain suspected to have a clinical lumbar instability: A randomized crossover design

BackgroundTheoretically, lumbopelvic stabilization techniques during hamstring muscle stretching could increase lumbar stiffness relative to hamstring muscle in individuals with a history of low back pain and suspected clinical lumbar instability. However, evidence to support this theory is limited. This study aimed to 1) determine changes in lumbopelvic, lumbar, and hip motions, and hamstring muscle length after stretching exercises with lumbopelvic stiffening or relaxing techniques, and 2) compare those changes between techniques.MethodsThis study used a randomized crossover design. Thirty-two participants with a history of low back pain and bilateral hamstring muscle tightness were recruited. The order of the first technique was randomly assigned. After a 2-day washout, participants were crossed over to the second technique. Motion data during active forward trunk bending and bilateral hamstring muscle length during passive knee extension were collected pre- and post-intervention.FindingsSignificant increases (P < 0.05) were found in bilateral hamstring muscle length for both techniques. However, stiffening technique demonstrated a significant decrease in lumbar motion (P < 0.05) and increase in hip motion (P < 0.05), while relaxing technique demonstrated trends showing increases in lumbar and hip motions (P = 0.134 and 0.115, respectively). The findings showed significantly greater improvement (P < 0.05) in lumbar and hip motions with stiffening technique.InterpretationThe findings suggest increased relative stiffness of the lumbar spine during hamstring muscle stretching can specifically lengthen bilateral hamstring muscle and decrease excessive lumbar motion. This stiffening technique may prevent excessive movement of the lumbar spine, thereby reducing the risk of recurrent low back pain.     

A multiple regression normalization approach to evaluation of gait in total knee arthroplasty patients

BackgroundGait features characteristic of a cohort may be difficult to evaluate due to differences in subjects' demographic factors and walking speed. The aim of this study was to employ a multiple regression normalization method that accounts for subject age, height, body mass, gender, and self-selected walking speed in the evaluation of gait in unilateral total knee arthroplasty patients.MethodsThree-dimensional gait analysis was performed on 45 total knee arthroplasty patients and 31 aged-matched controls walking at their self-selected speed. Gait data peaks including joint angles, ground reaction forces, net joint moments, and net joint powers were normalized using subject body mass, standard dimensionless equations, and a multiple regression approach that modeled subject age, height, body mass, gender, and self-selected walking speed.FindingsNormalizing gait data using subject body mass, dimensionless equations, and multiple regression approach resulted in a significantly lower knee adduction moment and knee extensor power in total knee arthroplasty patients compared to controls (p < 0.05). In contrast to normalization using body mass and dimensionless equations, multiple regression normalization greatly reduced variance in gait data by minimizing correlations with subject demographic factors and walking speed, resulting in significantly higher peak hip extension angles and peak hip flexion powers in total knee arthroplasty patients (p < 0.05).InterpretationTotal knee arthroplasty patients generate greater hip extension angles and hip flexor power and have a lower knee adduction moment than healthy controls. This gait pattern may be a strategy to reduce muscle and joint loading at the knee.     

Morphological and biomechanical adaptations of skeletal muscle in the recovery phase after immobilization in a rat

BackgroundRange of motion restriction following immobilization is spontaneously recovered at least in part by remobilization. However, the mechanisms underlying how muscles change with range of motion recovery are poorly understood. This study aimed to reveal morphological and biomechanical changes in the knee flexor semitendinosus muscle that contribute to knee joint contracture following the relief of immobilization.MethodsTo induce flexion contracture, we immobilized rat right knees by an external fixator at a flexed position for three weeks. After removal of the fixator, the joints were allowed to move freely (remobilization) for up to 14 days. We obtained muscle length and passive stiffness of the isolated semitendinosus muscles after measuring passive knee extension range of motion.FindingsThree weeks of immobilization induced range of motion reduction, as well as changes in morphological and biomechanical properties of the semitendinosus muscle, such as reduced muscle length and increment of passive stiffness leading to myogenic contracture. Joint immobilization-induced reduction of range of motion, representing flexion contracture, was partially reduced by 14 days of remobilization. Concomitantly, both muscle length and muscle stiffness returned to levels not significantly different from those in the contralateral side during this period.InterpretationThese results suggest that improvement of myogenic contracture during the early phase of remobilization occurs via both morphological and biomechanical adaptations.     

Hip flexor muscle size,strength and recruitment pattern in patients with acetabular labral tears compared to healthy controls

Acetabular labral tears are a source of hip pain and are considered to be a precursor to hip osteoarthritis. Hip flexor muscles contribute to hip joint stability and function but it is unknown if their size and function is altered in the presence of labral pathology. This study aimed to investigate hip flexor muscle size, strength and recruitment pattern in patients with hip labral pathology compared to control subjects. 12 subjects diagnosed with an unilateral acetabular labral tear were compared to 12 control subjects matched for age and gender. All subjects underwent magnetic resonance imaging (MRI) of their lumbo-pelvic region. Average muscle cross-sectional area (CSA) of the iliacus, psoas, iliopsoas, sartorius, tensor fascia latae and rectus femoris muscles were measured. Hip flexion strength was measured by an externally fixed dynamometer. Individual muscle recruitment pattern during a resisted hip flexion exercise task was measured by muscle functional MRI.Hip flexor muscle strength was found to be decreased in patients with labral pathology compared to control subjects (p < 0.01). No difference between groups or sides was found for hip flexor muscle size (all p > 0.17) and recruitment pattern (all p > 0.53).Decreased hip flexor muscle strength may affect physical function in patients with hip labral pathology by contributing to altered gait patterns and functional tasks. Clinical rehabilitation of these patients may need to include strengthening exercises for the hip flexor muscles.     

A comparison of two stretching programs for hamstring muscles: A randomized controlled assessor-blinded study

Most parameters regarding hamstring flexibility training programs have been investigated; however, the joint (i.e. hip or knee) on which the stretching should preferentially be focused needs to be further explored. This randomized controlled assessor-blinded study aimed to investigate the influence of this parameter. We randomly assigned 111 asymptomatic participants with tight hamstring muscles in three groups: a control group and two groups following a different home-based 8-week (five 10-minute sessions per week) hamstring stretching program (i.e. stretching performed by flexing the hip while keeping the knee extended [SH] or by first flexing the hip with a flexed knee and then extending the knee [SK]). Range of motion (ROM) of hip flexion and knee extension were measured before and after the stretching program by means of the straight leg raising test and the passive knee extension angle test, respectively. Eighty-nine participants completed the study. A significant increase in ROM was observed at post-test. Analyses showed significant group-by-time interactions for changes regarding all outcomes. Whereas the increase in hip flexion and knee extension ROM was higher in the stretching groups than in the CG (especially for the SH group p < 0.05), no differences between the two stretching groups were observed (p > 0.05). In conclusion, the fact that both stretching programs resulted in similar results suggests no influence of the joint at which the stretching is focused upon, as assessed by the straight leg raising and knee extension angle tests.     

Improvements in kinematics,muscle activity and pain during functional tasks in females with patellofemoral pain following a single patterned electrical stimulation treatment

BackgroundIndividuals with patellofemoral pain present with altered hip muscle activation, faulty movement patterns, and pain during functional tasks. Examining new treatment options to address these impairments may better treat those with patellofemoral pain. The purpose of this study was to determine if patterned electrical stimulation to the lower extremity affects muscle activity, movement patterns, and pain following a single treatment.MethodsFifteen females with patellofemoral pain were randomized to receive a single 15-minute treatment of either a patterned electrical neuromuscular stimulation or a sham. Peak kinematics of the knee, hip, and trunk, electromyography and pain were examined pre and post-intervention during a single leg squat and lateral step-down task. Group means and pre/post reduced kinematic values were also plotted during the entire task with 90% confidence intervals to identify differences in movement strategies.FindingsNo baseline differences were found in peak kinematics between groups. No pre to post-intervention differences in peak knee, hip and trunk kinematics were found, however differences were seen when the quality of movement across the entire tasks was assessed. The electrical stimulation group had improved knee flexion and hip abduction during the lateral step-down. A significant improvement in gluteus medius activation following patterned electrical neuromuscular stimulation occurred during the step-down (P = 0.039). Significant pain improvements were also seen in both the single leg squat (P = 0.025) and lateral step-down (P = 0.006).InterpretationA single treatment of patterned electrical neuromuscular stimulation improved muscle activation, lower extremity kinematics during functional tasks, and pain.     

Hip muscle weakness and reduced joint range of motion in patients with femoroacetabular impingement syndrome: a case-control study

BackgroundFemoroacetabular impingement (FAI) syndrome is a hip joint motion-related clinical disorder characterized by abnormal contact between the hip joint structures. Abnormal hip morphology and joint pain may impair the hip joint range of motion (ROM) and muscle function. However, FAI effects on hip joint ROM and muscle strength remain controversial.ObjectivesThe purpose of this study was to compare hip joint ROM and muscle strength between FAI syndrome patients and healthy controls.MethodsTwenty FAI syndrome male patients and 20 healthy male controls (CG) matched for age (FAI = 28 ± 6 years; CG = 27 ± 5 years), body mass (FAI = 81 ± 12 kg; CG = 80 ± 13 kg) and height (FAI = 177 ± 6 cm; CG = 178 ± 6 cm), participated in the study. Hip joint ROM for flexion, internal rotation and external rotation were assessed through goniometry. Maximal isometric strength for hip flexion, extension, abduction and adduction were evaluated through hand-held dynamometry.ResultsHip joint ROM was significantly lower in FAI syndrome patients compared with CG for passive flexion (−4%; effect size – ES = 0.65), active internal rotation (−42%; ES = 1.60), active external rotation (−28%; ES = 1.46) and passive external rotation (−23%; ES = 1.63). FAI patients’ hip extensors (−34%; ES = 1.46), hip adductors (−33%; ES = 1.32), and hip flexors (−25%; ES = 1.17) were weaker compared to the CG subjects.ConclusionsFAI syndrome patients presented both hip muscle weakness and reduced joint ROM compared to match CG.     

Trunk movement compensation identified by inertial measurement units is associated with deficits in physical performance,muscle strength and functional capacity in people with hip osteoarthritis

BackgroundTrunk movement compensation characterized as ipsilateral trunk lean and posterior rotation with respect to pelvis during stance phase of walking is common in people with hip osteoarthritis and a biomarker of deficits in physical function in older adults. However, the relationship between trunk movement compensation on deficits in physical performance, muscle strength and functional capacity is unknown.MethodsA cross-sectional study design was used. Two inertial measurement units were used to assess trunk movement compensation during the six-minute-walk-test. Knee extension, knee flexion and hip abduction strength were measured using hand-held dynamometer. Multivariate regression models, controlling for self-reported hip pain, were used to regress trunk movement compensation onto six-minute-walk-test and muscle strength measures. Pairwise t-tests were used to evaluate the difference trunk movement compensation has on functional capacity by comparing the first and last minute of the six-minute-walk-test.FindingsThirty-five participants (63.3 ± 7.4 years, 57% male, 28.6 ± 4.5 kg/m²) were enrolled. Greater trunk movement compensation was related to poorer six-minute-walk-test (p = 0.03; r = −0.46). Greater hip abduction weakness was related to increased trunk movement compensation in both the sagittal (p = 0.05; r = −0.44) and frontal (p = 0.04; r = −0.38) planes. Participants demonstrated greater frontal plane trunk movement compensation during the last minute compared to the first minute of the six-minute-walk-test (p < 0.01).InterpretationTrunk movement compensation, identified by inertial measure units, is a clinically relevant measure and has a moderate-to-strong relationship on deficits in physical performance, muscle strength and functional capacity. Inertial measurement units can be used as a practical means of measuring movement quality in the clinical setting.     

Relationship between wire EMG activity,muscle length,and torque of the hamstrings

OBJECTIVE: To determine the effect of change of muscle length on the torque and wire electromyographic activity of six knee flexor muscles. DESIGN: Maximum isometric knee flexion torque and wire EMG data were collected at nine different positions. BACKGROUND: In vivo EMG-length-tension relationship is difficult to determine because of the interaction between muscle length and moment arm. The study of two-joint muscles allows the change of muscle length at one joint while preserving stable mechanical relationships at the other. This model facilitates understanding of length-tension and EMG-length relationship in vivo. METHODS: Nineteen subjects performed maximum isometric knee flexion contraction at nine positions of varying hip and knee angles. Wire EMG activity was recorded from semitendionsus, semimembranosus, long and short head of the biceps femoris, gracilis and sartorious muscles. RESULTS: As the two-joint hamstrings were lengthened, torque was significantly increased. Maximum isometric torque ranged from 257 to 716 kg cm. The ratio of the torque values to EMG activity of all muscles was increased at longer muscle lengths. A change in the muscle length of the two-joint hamstrings did not produce a consistent change of EMG activity. The short head of the biceps femoris and sartorius muscles increased their activity as the angle of knee flexion increased. CONCLUSIONS: Maximum torque of knee flexion occurs at the most lengthened position of the hamstrings. EMG activity did not consistently change with the change in muscle length. RELEVANCE: Understanding in vivo length-tension relationship and associated EMG activity is important for designing rehabilitation protocols, tendon lengthening and transfer and interpretation of EMG data.     

Effects of hip and trunk muscle strengthening on hip function and lower limb kinematics during step-down task

BackgroundStrengthening of the hip and trunk muscles has the potential to change lower limb kinematic patterns, such as excessive hip medial rotation and adduction during weight-bearing tasks. This study aimed to investigate the effect of hip and trunk muscles strengthening on hip muscle performance, hip passive properties, and lower limb kinematics during step-down task in women.MethodsThirty-four young women who demonstrated dynamic knee valgus during step-down were divided into two groups. The experimental group underwent three weekly sessions of strengthening exercises for eight weeks, and the control group continued their usual activities. The following evaluations were carried out: (a) isokinetic maximum concentric and eccentric work of hip lateral rotators, (b) isokinetic hip passive torque of lateral rotation and resting transverse plane position, and (c) three-dimensional kinematics of the lower limb during step-down.FindingsThe strengthening program increased concentric (P < 0.001) and eccentric (P < 0.001) work of hip lateral rotators, and changed hip resting position toward lateral rotation (P < 0.001). The intervention did not significantly change hip passive torque (P = 0.089, main effect). The program reduced hip (P = 0.002), thigh (P = 0.024) and shank (P = 0.005) adduction during step-down task. Hip, thigh and knee kinematics in transverse plane and foot kinematics in frontal plane did not significantly modify after intervention (P ≥ 0.069, main effect).InterpretationHip and trunk strengthening reduced lower limb adduction during step-down. The changes in hip maximum work and resting position may have contributed to the observed kinematic effects.     

The acute effects of different hamstring muscle stretching techniques on reducing muscle resistance to movement by ultrasound elastography

ObjectiveMany stretching methods are applied on the hamstring muscles for reducing muscle resistance on movement. The aim of our study to investigate the acute effects of static stretching and the Mulligan traction straight leg raise (TSLR) technique administered to the hamstring muscles on reducing its resistance to movement.MethodsThe study included 22 healthy male volunteers (19.5 ± 0.98 years). After the individuals were randomly divided into two groups, static stretching was administered to the hamstring muscles in the first group and the Mulligan TSLR technique was administered on the same muscle in the second group. Active knee extension angles of the individuals were evaluated by a digital goniometer and muscle strain was assessed by ultrasound elastography.ResultsWhile there was a significant difference in all parameters in both groups after the treatment, the changes in the active knee extension angle and the strain index value of the biceps femoris musculotendinous junction were higher in the Mulligan TSLR group compared to the static stretching group (p < 0.05).ConclusionIt was concluded that, static stretching and the Mulligan TSLR technique administered to the hamstring muscles are effective ways to increase the range of motion. The Mulligan TSLR technique, however, can be opted in healthy individuals and patients since it is painless and more effective in reducing muscle resistance to movement and range of motion.     

Association between severity of hip chondrolabral injuries,dynamic hip muscle strength and quality of life: A cross-sectional study in patients with femoroacetabular impingement syndrome scheduled for hip arthroscopy

BackgroundWe assessed the association between: the severity of hip chondral or labral pathology with dynamic hip muscle strength or quality of life in patients with femoroacetabular impingement syndrome scheduled for hip arthroscopy. We also assessed the association between dynamic hip muscle strength with quality of life.MethodsEighty-three participants with femoroacetabular impingement syndrome scheduled for hip arthroscopy were included. We measured dynamic hip abduction and adduction muscle strength with an isokinetic dynamometer (Nm/kg), and quality of life with the iHoT-33 questionnaire. The severity of hip chondrolabral pathologies was scored using the modified Beck classification. Linear regression analyses were conducted to assess the association between severity of hip chondral or labral pathology with dynamic hip muscle strength and quality of life.FindingsThe regression analyses showed no association between the (i) severity of hip chondral (adjusted r²: 0.14) or labral (adjusted r²: 0.08) pathology and quality of life (P > 0.05), (ii) between the severity of hip chondral or labral pathology and dynamic hip abduction and adduction muscle strength (P > 0.05). Significant correlation was observed for quality of life and hip abduction (adjusted r²:0.29; P < 0.001) or adduction (adjusted r²: 0.32; P < 0.001) muscle strength.InterpretationThe severity of hip chondral or labral pathologies were not associated with quality of life or dynamic hip muscle strength in participants with femoroacetabular impingement syndrome. Greater dynamic hip abduction and adduction muscle strength were associated with better quality of life in participants with femoroacetabular impingement syndrome scheduled for hip arthroscopy.     

Effects of iliotibial band syndrome on pain sensitivity and gait kinematics in female runners: A preliminary study

BackgroundRunners with iliotibial band syndrome display symptoms similar to chronic tendinopathy and distinct gait patterns compared to healthy controls. Although altered pain processing has been demonstrated in chronic tendinopathies, central pain processing and its relationship to motor control has not been measured in iliotibial band syndrome. The purpose of this study was to examine pain sensitivity, hip strength, and gait kinematics in runners with and without iliotibial band syndrome.MethodsNine female runners with iliotibial band syndrome and eight healthy controls participated. Subjective pain was reported and pressure pain threshold measured at the bilateral foot, tibialis anterior, contralateral hand. Isometric hip strength was assessed. Three-dimensional joint angles were collected while running. Differences in pain and strength were determined using 1-way ANOVAs. Discrete hip and knee joint angles during stance phase were calculated and waveform analysis performed.FindingsRunners with iliotibial band syndrome exhibited bilaterally diminished pain at the foot (injured-limb: 1.54 (SD = 0.51); non-injured limb: 1.54 (SD = 0.55); control: 4.01 (SD = 2.30) kg, P < .001) and ipsilateral tibialis anterior (injured-limb: 2.33 (SD = 1.10); control: 6.13 (SD = 4.89) kg, P = .03). Hip strength was not different between groups. Runners with iliotibial band syndrome had greater hip adduction at touchdown, knee internal rotation during loading, and knee abduction and flexion at toe-off than controls.InterpretationRunners with iliotibial band syndrome demonstrated expanded somatic pain sensitivity without hip strength differences, but concomitant with altered gait patterns. Bilateral pain symptoms and gait deviations exist in runners with iliotibial band syndrome even with unilateral symptoms, highlighting the importance of bilateral assessment.     

Lean muscle volume of the thigh has a stronger relationship with muscle power than muscle strength in women with knee osteoarthritis

BackgroundThigh lean muscle and intramuscular fat have been implicated in the impairment of physical function observed in people with knee osteoarthritis. We investigated the relationships of quadriceps and hamstrings intramuscular fat fraction and lean muscle volume with muscle power and strength, controlling for neuromuscular activation, and physical performance in women with knee OA.MethodsWomen (n = 20) 55 years or older with symptomatic, radiographic knee osteoarthritis underwent a 3.0T magnetic resonance imaging scan of the thigh of their most symptomatic knee. Axial fat-separated images were analyzed using software to quantify intramuscular fat and lean muscle volumes of the quadriceps and hamstrings. To quantify strength and power of the knee extensors and flexors, participants performed maximum voluntary isometric contraction and isotonic knee extensions and flexions, respectively. Electromyography of the quadriceps and hamstrings was measured. Participants also completed five physical performance tests.FindingsQuadriceps and hamstrings lean muscle volumes were related to isotonic knee extensor (B = 0.624; p = 0.017) and flexor (B = 1.518; p = 0.032) power, but not knee extensor (B = 0.001; p = 0.615) or flexor (B = 0.001; p = 0.564) isometric strength. Intramuscular fat fractions were not related to isotonic knee extensor or flexor power, nor isometric strength. No relationships were found between intramuscular fat or lean muscle volume and physical performance.InterpretationMuscle power may be more sensitive than strength to lean muscle mass in women with knee osteoarthritis. Thigh lean muscle mass, but neither intramuscular nor intermuscular fat, is related to knee extensor and flexor power in women with knee osteoarthritis.