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To explore the effect of an isometric weighted Copenhagen adduction (WCA) exercise programme and an isometric unweighted Copenhagen adduction (CA) exercise programme on hip adduction strength, abduction strength and adduction:abduction strength ratio. Randomized controlled trial, with flat outcome structure. Rugby training facility. Thirty-one male rugby players. Between-group differences in hip adduction strength, abduction strength and adduction:abduction ratio were assessed using independent-sample t-tests. Within-group differences in hip strength were assessed using paired-sample t-tests. 15 participants were assigned to the CA group and sixteen to the WCA group. Post-intervention, a significant between-group difference in hip adduction:abduction strength ratio was observed (0.09 Nm/kg, p = 0.032) with large effect size (ES = 0.812). No significant between-group differences were evident for hip adduction strength (0.21 Nm/kg, p = 0.058) or hip abduction strength (0.01 Nm/kg, p = 0.856). The WCA group demonstrated significant increases in hip adduction (0.22 N/kg, +10 %, p = 0.008) and hip adduction:abduction ratio (0.06 N/kg, +7 %, p = 0.036), but not hip abduction (0.08 N/kg, +4 %, p = 0.055), following the 8-week programme. No significant changes in hip strength were observed in the CA group. A low-dose 8-week adductor exercise programme using the isometric WCA exercise elicits significant increases in hip adduction:abduction strength ratio when compared to an isometric CA exercise. •The isometric WCA demonstrates greater effect on the hip adduction:abduction strength ratio than the isometric CA exercise.•The isometric WCA exercise elicits significant within-group increases in hip strength.•The isometric CA exercise does not induce significant within-group change in hip strength.

Robotic exoskeletons are regarded as promising technologies for neurological gait rehabilitation but have been investigated comparatively little as training aides to facilitate active aging in the elderly. This study investigated the feasibility of an exoskeletal Active Pelvis Orthosis (APO) for cardiopulmonary gait training in the elderly. Ten healthy elderly volunteers exhibited a decreased (−26.6 ± 16.1%) Metabolic Cost of Transport (MCoT) during treadmill walking following a 4-week APO-assisted training program, while no significant changes were observed for a randomly assigned control group (n = 10) performing traditional self-paced overground walking. Moreover, robot-assisted locomotion was found to require 4.24 ± 2.57% less oxygen consumption than free treadmill walking at the same speed. These findings support the adoption of exoskeletal devices for the training of frail individuals, thus opening new possibilities for sustainable strategies for healthy aging.

Lower-limb wearable robotic devices can improve clinical gait and reduce energetic demand in healthy populations. To help enable real-world use, we sought to examine how assistance should be applied in variable gait conditions and suggest an approach derived from knowledge of human locomotion mechanics to establish a 'roadmap' for wearable robot design. We characterized the changes in joint mechanics during walking and running across a range of incline/decline grades and then provide an analysis that informs the development of lower-limb exoskeletons capable of operating across a range of mechanical demands. We hypothesized that the distribution of limb-joint positive mechanical power would shift to the hip for incline walking and running and that the distribution of limb-joint negative mechanical power would shift to the knee for decline walking and running. Eight subjects (6M,2F) completed five walking (1.25 m s-1) trials at -8.53°, -5.71°, 0°, 5.71°, and 8.53° grade and five running (2.25 m s-1) trials at -5.71°, -2.86°, 0°, 2.86°, and 5.71° grade on a treadmill. We calculated time-varying joint moment and power output for the ankle, knee, and hip. For each gait, we examined how individual limb-joints contributed to total limb positive, negative and net power across grades. For both walking and running, changes in grade caused a redistribution of joint mechanical power generation and absorption. From level to incline walking, the ankle's contribution to limb positive power decreased from 44% on the level to 28% at 8.53° uphill grade (p < 0.0001) while the hip's contribution increased from 27% to 52% (p < 0.0001). In running, regardless of the surface gradient, the ankle was consistently the dominant source of lower-limb positive mechanical power (47-55%). In the context of our results, we outline three distinct use-modes that could be emphasized in future lower-limb exoskeleton designs 1) Energy injection: adding positive work into the gait cycle, 2) Energy extraction: removing negative work from the gait cycle, and 3) Energy transfer: extracting energy in one gait phase and then injecting it in another phase (i.e., regenerative braking).

Evidence for performance decrements following prolonged static stretching (SS) has led to a paradigm shift in stretching routines within a warm-up. Rather than SS, dynamic stretching (DS) and dynamic activity (DA) have replaced SS within warm-up routines. The objective of the present study was to compare the effect of differing lower limb SS durations (30 [SS30s], 60 [SS60s] or 120 s [SS120s] of SS per muscle group or no-stretch control) within a comprehensive warm-up protocol consisting of aerobic activity, DS and DA. Sixteen male participants completed the four stretching conditions in a randomized order, after a 5-min low-intensity (cycle) warm-up and before a DS/DA component on separate days. Tests included passive hip and knee ranges of motion (ROM), maximum voluntary knee extensor/flexor force, force produced at 100 ms (F100), vertical jump height and evoked knee extensor contractile properties. For hip flexion (hamstrings) ROM, SS120s provided the largest increase (5.6–11.7%) followed by SS60s (4.3–11.4%), control (4.4–10.6%) and SS30s (3.6–11.1%). For knee flexion (quadriceps) ROM, SS30s provided the largest increase (9.3–18.2%) followed by SS120s (6.5–16.3%), SS60s (7.2–15.2%) and control (6.3–15.2%). There were decreases in quadriceps F100 following SS in SS120s (29.6%) only. There were increases in vertical jump performance in the control (6.2%), SS60s (4.6%) and SS30s (3.3%). While 120 s SS per muscle increased ROM, even within a comprehensive warm-up routine, it also elicited notable performance decrements. However, moderate durations of SS were observed to improve ROM whilst either having negligible or beneficial (but not detrimental) effects on specific aspects of athletic performance.

We aimed to compare the effects between non-vibration foam rolling (NVFR) and vibration foam rolling (VFR) on visual analogic scale (VAS), pressure pain threshold (PPT), oxygen saturation (SmO2), countermovement jump (CMJ) and hip and knee range of movement (ROM) after eliciting muscle damage through eccentric acute exercise using an inertial flywheel. Thirty-eight healthy volunteers (32 men, 6 women; aged 22.2±3.2 years) were randomly assigned in a counter-balanced fashion to either a VFR or NVFR protocol group. All participants performed a 10x10 (sets x repetitions) eccentric squat protocol to induce muscle damage. The protocols were administered 48-h post-exercise, measuring VAS, PPT, SmO2, CMJ and ROM, before and immediately post-treatment. The treatment technique was repeated on both legs for 1 minute for a total of five sets, with a 30-s rest between sets. The VFR group showed substantially greater improvements (likely to very likely) in the passive VAS (VFR -30.2%, 90% CI -66.2 to -12.8) with chances for lower, similar or greater VAS compared with the NVFR group of 82%, 14% and 4%, respectively and passive extension hip joint ROM (VFR 9.3%, 90% CI 0.2-19.2) with chances for lower, similar or greater ROM compared with the NVFR group of 78%, 21% and 1%, respectively. For intragroup changes, we observed substantial improvements in VAS (p=.05), lateral vastus, rectus femoris and medial vastus PPT. The results suggest that the VFR group achieved greater short-term benefits in pain perception and passive extension hip joint ROM. Both protocols were effective in improving PPT, SmO2, CMJ and knee joint ROM. The enhanced improvement in VAS and hip ROM measures could have significant implications for VFR treatment.

Patellofemoral pain (PFP) is the most common injury in running and jumping athletes. Randomized controlled trials suggest that incorporating hip and core strengthening (HIP) with knee-focused rehabilitation (KNEE) improves PFP outcomes. However, no randomized controlled trials have, to our knowledge, directly compared HIP and KNEE programs. To compare PFP pain, function, hip- and knee-muscle strength, and core endurance between KNEE and HIP protocols after 6 weeks of rehabilitation. We hypothesized greater improvements in (1) pain and function, (2) hip strength and core endurance for patients with PFP involved in the HIP protocol, and (3) knee strength for patients involved in the KNEE protocol. Randomized controlled clinical trial. Four clinical research laboratories in Calgary, Alberta; Chicago, Illinois; Milwaukee, Wisconsin; and Augusta, Georgia. Of 721 patients with PFP screened, 199 (27.6%) met the inclusion criteria (66 men [31.2%], 133 women [66.8%], age = 29.0 ± 7.1 years, height = 170.4 ± 9.4 cm, weight = 67.6 ± 13.5 kg). Patients with PFP were randomly assigned to a 6-week KNEE or HIP protocol. Primary variables were self-reported visual analog scale and Anterior Knee Pain Scale measures, which were conducted weekly. Secondary variables were muscle strength and core endurance measured at baseline and at 6 weeks. Compared with baseline, both the visual analog scale and the Anterior Knee Pain Scale improved for patients with PFP in both the HIP and KNEE protocols (P < .001), but the visual analog scale scores for those in the HIP protocol were reduced 1 week earlier than in the KNEE group. Both groups increased in strength (P < .001), but those in the HIP protocol gained more in hip-abductor (P = .01) and -extensor (P = .01) strength and posterior core endurance (P = .05) compared with the KNEE group. Both the HIP and KNEE rehabilitation protocols produced improvements in PFP, function, and strength over 6 weeks. Although outcomes were similar, the HIP protocol resulted in earlier resolution of pain and greater overall gains in strength compared with the KNEE protocol.

The Copenhagen adductor exercise (CAE) is used for groin muscle strengthening. While these muscles primarily act in the frontal plane, the hip adductor muscles may also act in the sagittal and transverse planes. Therefore, the CAE likely imposes three-dimensional (3D) muscular demands at both the hip and knee. This study aimed to quantify the 3D hip and knee joint loading during variations of the CAE. Eleven men and 13 women performed the exercise with the support stand at the knee, ankle, and midway between the knee and ankle. Ground reaction forces under the stand and reflective markers trajectories were recorded to calculate hip and knee net joint moments (NJM). Hip adductor NJM was largest for the ankle support (1.54 ± 0.23 Nm·kg−1) and smallest for the knee support (0.93 ± 0.16 Nm·kg−1; P < 0.001). Most participants had a hip extensor NJM, that was also greater for more distal support locations (Δankle-mid = −0.10 ± 0.21 Nm·kg−1; Δankle-knee =  −0.20 ± 0.27 Nm·kg−1; P < 0.001). Support locations distal to the knee had knee adductor and flexor NJM. The hip and knee sagittal plane NJMs were strongly correlated with transverse plane thigh (r = 0.97–0.98, P < 0.017) and shank (r = 0.89–0.93, P < 0.017) orientations, respectively. Medial thigh rotation was associated with a hip flexor NJM while lateral thigh rotation was associated with a hip extensor NJM. CAE requires frontal and sagittal plane muscle efforts at the hip and knee, which are greater for more distal support locations.

ObjectivesTo test (i) if greater foot pronation (measured as midfoot width mobility) is associated with better outcomes with foot orthoses treatment, compared with hip exercises and (ii) if hip exercises are superior to foot orthoses, irrespective of midfoot width mobility.MethodsA two-arm parallel, randomised superiority clinical trial was conducted in Australia and Denmark. Participants (18–40 years) were included who reported an insidious onset of knee pain (≥6 weeks duration); ≥3/10 numerical pain rating, that was aggravated by activities (eg, stairs, squatting, running). Participants were stratified by midfoot width mobility (high ≥11 mm change in midfoot width) and site, randomised to foot orthoses or hip exercises and blinded to objectives and stratification. Success was defined a priori as much better or better on a patient-perceived 7-point scale at 12 weeks.ResultsOf 218 stratified and randomised participants, 192 completed 12-week follow-up. This study found no difference in success rates between foot orthoses versus hip exercises in those with high (6/21 vs 9/20; 29% vs 45%, respectively) or low (42/79 vs 37/72; 53% vs 51%) midfoot width mobility. There was no association between midfoot width mobility and treatment outcome (Interaction effect p=0.19). This study found no difference in success rate between foot orthoses versus hip exercises (48/100 vs 46/92; 48% vs 50%).ConclusionMidfoot width mobility should not be used to help clinicians decide which patient with patellofemoral pain might benefit most from foot orthoses. Clinicians and patients may consider either foot orthoses or hip exercises in managing patellofemoral pain.Trial registration numberACTRN12614000260628.

Impaired hip muscle function may cause movement coordination deficits that increase lower extremity injury risks. We examined whether hip and knee coordination is altered during single-limb step-downs following a hip extensor fatigue protocol. Forty participants in this randomized controlled trial performed 20 single-limb step-downs before and after completing either a fatigue protocol or a sham fatigue protocol. Means and SDs of sagittal and frontal plane hip and knee kinematics were measured. Nonlinear measures of coupled hip and knee coordination were examined with cross recurrence quantification analyses. Pre- to post-fatigue change scores were analyzed inferentially (α = 0.05). The fatigue protocol induced 22.2% strength reduction in the fatigue group, versus 4% reduction in the sham group. Neither the magnitude nor variability in sagittal and frontal plane hip and knee kinematics changed following the fatigue protocol (P > .05, small effect sizes). Participants in the fatigue group, however, performed post-fatigue step-downs with greater cross determinism (P = .046, effect size = 0.71) and mean line (P = .038, effect size = 0.74) in sagittal plane hip and frontal plane knee coupling, whereas participants in the sham-control group performed step-downs with reductions in those measures. In the fatigued state, participants performed repeated step-downs with subtle increases in cross determinism and cross mean line, which implies they performed the task with greater predictability of hip and knee coupling and less adaptability. The findings may provide insight into coupled movement patterns and their reflection of motor control.

Three-dimensional gait analysis has been used extensively in research. During walking, the external hip adduction moment (EHAM) has been used as a surrogate measure of joint loading in individuals with hip osteoarthritis and inconsistency between previous studies could be attributed to the inconsistency of static standing trials. The present study was designed to examine the effects of static trial foot position on hip and ankle kinetics and kinematics variables during walking. Twelve participants were recruited and completed three static trials: 20° toe-out, straight (0°), and 20° toe-in. Five walking trials (own pace and shoes) were collected. The dynamic trials were analysed using three static trials. The first-peak, trough, and second-peak EHAMs and other hip and ankle kinematics and kinetics were compared between the conditions using repeated-measures analysis of variance. The first peak, trough, and second peak EHAMs showed a significant increase during movement from 20° toe-in to 20° toe-out by 5.87 %, 7.74 %, and 7.68 %, respectively. Furthermore, significant changes were found in hip flexion angle, hip sagittal plane range of motion angle, hip adduction and abduction angles, hip internal and external rotation angles, hip internal rotation moment, ankle dorsiflexion and plantarflexion moments, and ankle inversion and eversion moments. In this study, the change in foot position during the within-subject trials affected the first peak, trough, and second peak EHAMs and other kinetic and kinematic variables during walking. Therefore, this study highlights the importance to standardise the foot position in static trials to avoid masking or accentuating the actual changes.