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The effects of a 12‐week gait retraining program on the adaptation of the medial gastrocnemius (MG) and muscle‐tendon unit (MTU) were investigated. 26 runners with a rearfoot strike pattern (RFS) were randomly assigned to one of two groups: gait retraining (GR) or control group (CON). MG ultrasound images, marker positions, and ground reaction forces (GRF) were collected twice during 9 km/h of treadmill running before and after the intervention. Ankle kinetics and the MG and MTU behavior and dynamics were quantified. Runners in the GR performed gradual 12‐week gait retraining transitioning to a forefoot strike pattern. After 12‐week, (1) ten participants in each group completed the training; eight participants in GR transitioned to non‐RFS with reduced foot strike angles; (2) MG fascicle contraction length and velocity significantly decreased after the intervention for both groups, whereas MG forces increased after intervention for both groups; (3) significant increases in MTU stretching length for GR and peak MTU recoiling velocity for both groups were observed after the intervention, respectively; (4) no significant difference was found for all parameters of the series elastic element. Gait retraining might potentially influence the MG to operate at lower fascicle contraction lengths and velocities and produce greater peak forces. The gait retraining had no effect on SEE behavior and dynamics but did impact MTU, suggesting that the training was insufficient to induce mechanical loading changes on SEE behavior and dynamics. [ABSTRACT FROM AUTHOR]

Objectives: Popliteal artery entrapment syndrome (PAES) is a rare condition where musculoskeletal structures compress the popliteal artery (POPA) leading to vascular compromise. This study investigates the effect of dynamic plantar‐ and dorsi‐flexion loading on POPA hemodynamic parameters to develop a robust diagnostic ultrasound‐based protocol for diagnosing functional PAES. Methods: Healthy individuals (n = 20), recreational athletes (n = 20), and symptomatic (n = 20) PAES patients were consented. Triplex ultrasound imaging of lower limb arteries was performed (n = 120 limbs). Proximal and distal POPA's in dorsi‐/plantar‐flexion, in prone and erect positions, were imaged at rest and flexion. Peak systolic velocities (cm/s) and vessel diameter (antero‐posterior, cm) was measured. Results: Distal vessel occlusion was noted across all three groups whilst prone during plantar‐flexion (62.7%). POPA occlusion was only noted in the proximal vessel within the patient group (15.8%). When prone, 50% of control (n = 40 limbs), 70% of athletes (n = 40 limbs), and 65% of patients (n = 40 limbs) had distal POPA occlusion in plantar‐flexion. When prone, recreational athletes (5%), and patients (12.5%) had distal POPA compression under dorsi‐flexion. POPA occlusions with the patient in erect position were only noted in the symptomatic patient group under both dorsi‐flexion (15.8%) and plantar‐flexion (23.7%). Conclusion: Compression of the POPA on ultrasound should not be the sole diagnostic criteria for PAES. POPA compression exists in asymptomatic individuals, primarily under prone plantar‐flexion. To reduce false positives, ultrasound‐based protocols should focus on scanning patients in the erect position only to diagnose PAES, rather than asymptomatic POPA compression. A distinction should be made between the two. [ABSTRACT FROM AUTHOR]

Purpose: The current biomechanical research on the application of Kinesio taping (KT) to patients with chronic ankle instability (CAI) has focused on testing the expected movements. However, unexpected movements are more common in actual sports. Therefore, the present study aimed to investigate the effects of KT on the biomechanical characteristics of the knee and ankle joints during unexpected jumping movements. Methods: Twenty‐one patients with unilateral CAI were recruited to capture the biomechanical parameters during unexpected jumping movements under different interventions: no taping (NT), placebo taping (PT), and KT. A one‐way repeated measures analysis of variance was used to compare the differences in knee and ankle biomechanical characteristics among patients with CAI between the three intervention conditions. Results: At initial contact, the KT group demonstrated a significant decrease in ankle plantarflexion and knee flexion angles compared to the NT group (p < 0.05). At the early landing phase, the KT group had a significant increase in peak ankle dorsiflexion angle, peak ankle eversion angle, peak ankle dorsiflexion moment, and peak ankle eversion moment compared to the NT and PT groups (p < 0.05). Furthermore, the KT group had a significantly reduced peak knee flexion angle, peak knee eversion angle, and peak vertical ground reaction force (p < 0.05) compared to the NT and PT groups. Conclusion: KT significantly improves the sprain‐prone touchdown posture of patients with CAI. And reducing the risk of ankle sprains during the early landing phase by promoting ankle dorsiflexion and eversion angles and moments. [ABSTRACT FROM AUTHOR]

Torsion of the Achilles tendon (AT) enhances tensile strength, but a high degree of torsion might also be a risk factor for Achilles tendinopathy, due to greater internal compression exerted during tensile loading. However, evidence supporting the grounds for this assumption is lacking. Hence, we aimed to investigate the impact of AT torsion type on intratendinous pressure. Eighteen human fresh frozen cadaveric legs were mounted in a testing rig and a miniature pressure catheter was placed through ultrasound‐guided insertion in the midportion region of the AT. Intratendinous pressure was measured during a simulated straight‐knee calf stretch and eccentric heel drop. The AT was then carefully dissected and classified into Type I (least), Type II (moderate), and Type III (extreme) torsion. Of the ATs examined, nine were found to have Type I torsion (50%), nine Type II (50%), and none Type III. It was found that the intratendinous pressure of the AT increased exponentially with ankle dorsiflexion during both exercises (p < 0.001) and that this increase was greater in ATs with Type II torsion than Type I torsion (p < 0.05). This study provides the first biomechanical data to support the hypothesis that in athletes with a high degree of torsion in the AT, the midportion area will experience more internal compression during exercise, for example, calf stretching and eccentric heel drops. Whether this phenomenon is also associated with an elevated risk for Achilles tendinopathy needs further prospective investigation. [ABSTRACT FROM AUTHOR]

Background: Limited dorsiflexion range of motion (DFROM) is a risk factor for lateral ankle sprain. However, varied DFROM exists within the chronic ankle instability (CAI) population, and how the variability may influence altered movement patterns during landing is unclear. Objective: The purpose of this study was to identify different movement strategies during maximal jump landing/cutting among CAI patients classified by varied DFROM. Methods: One hundred CAI subjects were classified into 3 subgroups based on their DFROM, measured by the weight‐bearing lunge test: a Hypo‐ (≤40°), Normal‐ (40–50°), and Hyper‐DFROM group (≥50°). Participants completed five trials of maximal jump landing/cutting. Lower extremity joint angles and EMG activation of seven muscles were collected from initial contact to toe‐off. Functional analyses of variance were used to evaluate between‐group differences for these outcome variables. Results: Hypo‐DFROM group (14M, 10F) displayed the reduced ankle dorsiflexion and inversion angles with increased hip flexion angle as a compensatory kinematic chain movement strategy. In addition, motion restrictions of the ankle are associated with altered muscle activation in both distal and proximal muscles during landing/cutting. Normal‐DFROM (25M, 30F) and Hyper‐DFROM (11M, 10F) groups also have different movement strategies including greater inversion angle and less EMG activation, which could contribute to further ankle injuries. Conclusions: Our data suggest that limited DFROM negatively affects the ankle joint during demanding movement within the CAI population. These movement patterns in CAI patients with pathomechanical deficits could contribute to further ankle sprains. [ABSTRACT FROM AUTHOR]

Rehabilitation is an important treatment for non‐insertional Achilles tendinopathy. To date, eccentric loading exercises (ECC) have been the predominant choice; however, mechanical evidence underlying their use remains unclear. Other protocols, such as heavy slow resistance loading (HSR), have shown comparable outcomes, but with less training time. This study aims to identify the effect of external loading and other variables that influence Achilles tendon (AT) force in ECC and HSR. Ground reaction force and kinematic data during ECC and HSR were collected from 18 healthy participants for four loading conditions. The moment arms of the AT were estimated from MRIs of each participant. AT force then was calculated using the ankle torque obtained from inverse dynamics. In the eccentric phase, the AT force was not larger than in the concentric phase in both ECC and HSR. Under the same external load, the force through the AT was larger in ECC with the knee bent than in HSR with the knee straight due to increased dorsiflexion angle of the ankle. Multivariate regression analysis showed that external load and maximum dorsiflexion angle were significant predictors of peak AT force in both standing and seated positions. Therefore, to increase the effectiveness of loading the AT, exercises should apply adequate external load and reach maximum dorsiflexion during the movement. Peak dorsiflexion angle affected the AT force in a standing position at twice the rate of a seated position, suggesting standing could prove more effective for the same external loading and peak dorsiflexion angle. [ABSTRACT FROM AUTHOR]

Athletic groin pain (AGP) is a chronic, painful condition which is prevalent in players of field sports that require rapid changes of direction. Following successful rehabilitation, systematic changes have been observed in the kinetics and kinematics of pre‐planned change of direction maneuvers, providing insight into potential foci for rehabilitation monitoring and for the assessment of interventions. However, changing direction in field sports is often reactive rather than pre‐planned, and it is not known whether such post‐rehabilitation changes are seen in reactive maneuvers. We analyzed the stance phase kinetics and kinematics of a 90° reactive cutting maneuver in 35 AGP patients before and after a successful exercise intervention program. Following the intervention, transverse plane rotation of the pelvis toward the intended direction of travel increased, and the body center of mass was positioned more anteriorly relative to the center of pressure. Ankle dorsiflexion also increased, and participants demonstrated greater ankle plantar flexor internal moment and power during the second half of stance. These findings provide insight into mechanical variables of potential importance in AGP, as identified during a maneuver based on a common sporting task. [ABSTRACT FROM AUTHOR]

High‐resolution ultrasound (US) has helped to characterize the "tennis leg injury" (TL). However, no specific classifications with prognostic value exist. This study proposes a medial head of the gastrocnemius injury classification based on sonographic findings and relates this to the time to return to work (RTW) and return to sports (RTS) to evaluate the prognostic value of the classification. 115 subjects (64 athletes and 51 workers) were retrospectively reviewed to asses specific injury location according to medial head of the gastrocnemius anatomy (myoaponeurotic junction; gastrocnemius aponeurosis (GA), free gastrocnemius aponeurosis (FGA)), presence of intermuscular hematoma, and presence of gastrocnemius‐soleus asynchronous movement. Return to play (RTP; athletes) and return to work (RTW; occupational) days were recorded by the treating physician. This study proposes 5 injury types with a significant relation to RTP and RTW (P <.001): Type 1 (myoaponeurotic injury), type 2A (gastrocnemius aponeurosis injury with a <50% affected GA width), type 2B (gastrocnemius aponeurosis with >50% affected GA width), type 3 (free gastrocnemius aponeurosis (FGA) tendinous injury), and type 4 (mixed GA and FGA injury). The longest RTP/RTW periods were associated with injuries with FGA involvement. Intermuscular hematoma and Gastrocnemius‐soleus asynchronous motion during dorsiflexion and plantarflexion were observed when the injury affected >50% of the GA width, with or without associated FGA involvement, and this correlated with a worse prognosis. The proposed classification can be readily applied in the clinical setting although further studies on treatment options are required. [ABSTRACT FROM AUTHOR]

Purpose: Single‐leg cycling exercise is one of the most potent, but underutilized, stimuli for promoting peripheral muscle respiratory capacity. Special ergometers used to facilitate single‐leg cycling, while maintaining biomechanics similar to double‐leg cycling, are not widely available. This lack of availability of specialized ergometers may explain why single‐leg cycling has not been widely implemented as standard clinical practice. Therefore, we explored the extent to which participants could emphasize one leg and de‐emphasize the other to perform "single‐leg emphasis cycling" using standard cycle ergometers. Methods: Sixteen athletic participants performed single‐leg emphasis cycling, emphasizing each leg in separate trials, and double‐leg cycling. Pedal forces and limb kinematics were collected and used to calculate joint‐specific work and power at the ankle, knee, and hip. Results: Study participants were able to produce approximately three times as much power with their emphasized leg compared to the de‐emphasized leg during single‐leg emphasis cycling. Ankle plantar flexion, dorsiflexion, knee extension, and hip extension work produced during single‐leg emphasis cycling did not differ from those during double‐leg cycling (all P >.60). Hip and knee flexion work during single‐leg emphasis cycling exhibited small but significant differences (both P <.05) from double‐leg cycling. Conclusions: These results demonstrate that single‐leg emphasis cycling provides a convenient alternative to single‐leg cycling requiring specialized ergometers, therefore, facilitating improved training in clinical and athletic populations using commonly available equipment. Further, biomechanics during single‐leg emphasis cycling closely approximated double‐leg cycling ensuring that training adaptations are highly applicable to double‐leg cycling. [ABSTRACT FROM AUTHOR]

Purpose: Physical preparation of competitive surfers includes substantial dry‐land training. It is currently unknown, however, how closely these exercises replicate surfing maneuvers performed in the ocean. This study compared the technique features displayed by surfers when landing simulated aerial maneuvers on land to critical features previously established as necessary for surfers to successfully land aerials in the ocean during competition. Methods: Fourteen competitive surfers (age 20.6 ± 5.7 years, height 178.1 ± 9.50 cm, mass 70.6 ± 10.8 kg) were recruited to perform two variations of a simulated aerial task, a Frontside Air (FA) and Frontside Air Reverse (FAR). Joint ranges of motion (ROM), center of pressure, and apparent gaze data were collected during the landing event. Paired t tests or Wilcoxon signed‐rank tests were used to identify any significant differences in the outcome variables between the two aerial tasks. Results: Participants displayed 100% and 60% of the critical features associated with successfully landing a FA and FAR, respectively. In both the simulated FA and FAR, participants landed in 1.0‐3.7° of dorsiflexion, moving through significantly less ankle joint ROM in the lead limb during the FAR (P <.01). Participants also displayed significantly less knee and hip ROM (P =.002‐.048) while landing the FAR compared to the FA. Conclusion: The simulated FA and FAR tasks are appropriate training tools for surfers to replicate most of the critical features that a surfer should display to successfully land aerial maneuvers in the ocean. These tasks therefore enable surfers to practice these complex movements in a controlled environment. [ABSTRACT FROM AUTHOR]

Introduction: The isometric force attained after active stretch is greater than that attained in a purely isometric contraction. This phenomenon is called residual force enhancement (RFE). The purpose was to examine the influence of isometric preactivation conducted just before active stretch on the magnitude of RFE in plantar flexors. Methods: In the control condition, subjects conducted isometric contraction at 15° of dorsiflexion. In the no preactivation condition, the isometric contraction at 15° of dorsiflexion was conducted after an eccentric contraction from 0° to 15° of dorsiflexion. In the isometric preactivation condition, an isometric contraction was conducted for preactivation before conducting the same routine as in the no preactivation condition. Isometric torque at the end of isometric contraction at 15° of dorsiflexion was compared among conditions to examine whether isometric preactivation affects the magnitude of RFE. The fascicle behaviors of the medial gastrocnemius were recorded by ultrasonography. Results: The isometric torque attained in the preactivation condition was greater than that in the control condition (P = 0.017). There was no significant difference between no preactivation and control conditions (P = 0.744). The magnitude of fascicle elongation during active stretch was greater in the preactivation than in the no preactivation condition (P = 0.002). Conclusion: Compared to the control condition, greater isometric torque was observed only in the preactivation condition, indicating that substantial RFE was induced only in the preactivation condition. This difference would be explained by the lesser degree of fascicle elongation during active stretch in the no preactivation condition. [ABSTRACT FROM AUTHOR]

The acute effects of two dynamic stretching (DS) protocols on changes in the ankle range of motion (RoM), neuromechanical, and sensorimotor properties of the plantarflexor muscle group were examined. Eighteen participants received slow (SDS) or fast dynamic stretching (FDS) on two separate days. Outcome measures were assessed pre‐ and 2 minutes post‐interventions, and included maximum dorsiflexion angle, maximum isometric torque at neutral ankle position, maximum concentric and eccentric torques, force matching capacity, joint position sense and medial gastrocnemius muscle and tendon strain. Possibly and likely small increases in dorsiflexion RoM were observed after SDS (mean ± 90% confidence intervals; 1.8 ± 1.2°) and FDS (2.1 ± 1.2°), respectively. Very likely moderate decreases in muscle strain after SDS (−38.0 ± 20.6%) and possibly small decrease after FDS (−13.6 ± 21.2%) were observed. SDS resulted in a likely beneficial small increase in tendon strain (25.3 ± 29.7%) and a likely beneficial moderate increase after FDS (41.4 ± 44.9%). Effects on strength were inconsistent. Possibly small effect on positional error after SDS (−27.1 ± 37.5%), but no clear effect after FDS was observed. Both DS protocols increased RoM, and this was more due to an increase in tendon elongation rather than the muscle. However, SDS showed greater improvement than FDS in both neuromechanical and sensorimotor performance, and hence, SDS can be recommended as part of warm‐up in sporting contexts. [ABSTRACT FROM AUTHOR]

Although performing aerial maneuvers can increase wave score and winning potential in competitive surfing, the critical features underlying successful aerial performance have not been systematically investigated. This study aimed to analyze highly skilled aerial maneuver performance and to identify the critical features associated with successful or unsuccessful landing. Using video recordings of the World Surf League's Championship Tour, every aerial performed during the quarterfinal, semifinal, and final heats from the 11 events in the 2015 season was viewed. From this, 121 aerials were identified with the Frontside Air (n = 15) and Frontside Air Reverse (n = 67) being selected to be qualitatively assessed. Using chi‐squared analyses, a series of key critical features, including landing over the center of the surfboard (FS Air χ2 = 14.00, FS Air Reverse χ2 = 26.61; P < .001) and landing with the lead ankle in dorsiflexion (FS Air χ2 = 3.90, FS Air Reverse χ2 = 13.64; P < .05), were found to be associated with successful landings. These critical features help surfers land in a stable position, while maintaining contact with the surfboard. The results of this study provide coaches with evidence to adjust the technique of their athletes to improve their winning potential. [ABSTRACT FROM AUTHOR]

We investigated the effects of the initial length of the muscle‐tendon unit (MTU) and muscle pre‐activation on muscle‐tendon interactions during plantarflexion performed at maximal velocity. Ultrasound images of gastrocnemius medialis were obtained on 11 participants in three conditions: (a) active plantarflexion performed at maximal velocity from three increasingly stretched positions (10°, 20°, and 30° dorsiflexion), (b) passive plantarflexion induced by a quick release of the ankle joint from the same three positions, and (c) pre‐activation, which consisted of a maximal isometric contraction of the plantarflexors at 10° of dorsiflexion followed by a quick release of ankle joint. During the active condition at maximal velocity, initial MTU stretch positively influenced ankle joint velocity (+15.3%) and tendinous tissues shortening velocity (+37.6%) but not the shortening velocity peak value reached by muscle fascicle. The muscle fascicle was shortened during the passive condition; however, its shortening velocity never exceeded peak velocity measured in the active condition. Muscle pre‐activation resulted in a considerable increase in ankle joint (+114.7%) and tendinous tissues velocities (+239.1%), although we observed a decrease in muscle fascicle shortening velocity. During active plantarflexion at maximal velocity, initial MTU length positively influences ankle joint velocity by increasing the contribution of tendinous tissues. Although greater initial stretch of the plantarflexors (ie, 30° dorsiflexion) increased the passive velocity of the fascicle during initial movement, its peak velocity was not affected. As muscle pre‐activation prevented reaching the maximal muscle fascicle shortening velocity, this condition should be used to characterize tendinous tissues rather than muscle contractile properties. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the influence of a single static, ballistic, or proprioceptive neuromuscular facilitation ( PNF) stretching exercise on the various muscle-tendon parameters of the lower leg and to detect possible differences in the effects between the methods. Volunteers ( n = 122) were randomly divided into static, ballistic, and PNF stretching groups and a control group. Before and after the 4 × 30 s stretching intervention, we determined the maximum dorsiflexion range of motion (RoM) with the corresponding fascicle length and pennation angle of the gastrocnemius medialis. Passive resistive torque ( PRT) and maximum voluntary contraction ( MVC) were measured with a dynamometer. Observation of muscle-tendon junction ( MTJ) displacement with ultrasound allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate stiffness. Although RoM increased (static: +4.3%, ballistic: +4.5%, PNF: +3.5%), PRT (static: −11.4%, ballistic: −11.5%, PNF: −13,7%), muscle stiffness (static: −13.1%, ballistic: −20.3%, PNF: −20.2%), and muscle-tendon stiffness (static: −11.3%, ballistic: −10.5%, PNF: −13.7%) decreased significantly in all the stretching groups. Only in the PNF stretching group, the pennation angle in the stretched position (−4.2%) and plantar flexor MVC (−4.6%) decreased significantly. Multivariate analysis showed no clinically relevant difference between the stretching groups. The increase in RoM and the decrease in PRT and muscle-tendon stiffness could be explained by more compliant muscle tissue following a single static, ballistic, or PNF stretching exercise. [ABSTRACT FROM AUTHOR]

Previous research in Irish dancing ( ID) has recorded high levels of pain/injury. Screening protocols in other genres have been developed to identify at-risk dancers. The aims of the study were to examine the factors that relate to absence from dancing because of musculo-skeletal pain/injury in ID, and to inform guidelines for the development of an evidence-based screening protocol. Baseline subjective data ( n = 85) and physical data ( n = 84) were gathered. Subjects completed a monthly online questionnaire for 1 year providing data on general physical and psychological health and rates of pain/injury. Subjects were allocated to a 'More Time Absent ( MTA)' or 'Less Time Absent ( LTA)' category depending on their duration of absence from performance over the year. Eighty-four subjects completed the year-long follow-up ( MTA: n = 32; LTA: n = 52). Two hundred seventy-eight complaints of pain/injury were recorded. Factors significantly associated with membership of the MTA group included greater anger-hostility ( P = 0.003), more subjective health complaints ( P = 0.026), more severe previous pain/injury ( P = 0.017), more general everyday pain ( P = 0.020), more body parts affected by pain/injury ( P = 0.028), always/often dancing in pain ( P = 0.028), and insufficient sleep ( P = 0.043). Several biopsychosocial factors appear to be associated with absence from ID because of pain/injury. Biopsychosocial screening protocols and prevention strategies may best identify at-risk dancers. [ABSTRACT FROM AUTHOR]

Mechanical loading of the Achilles tendon during isolated eccentric contractions could induce immediate and region-dependent changes in mechanical properties. Three-dimensional ultrasound was used to examine the immediate effect of isolated eccentric exercise on the mechanical properties of the distal (free tendon) and proximal (gastrocnemii) regions of the Achilles tendon. Participants ( n = 14) underwent two testing sessions in which tendon measurements were made at rest and during a 30% and 70% isometric plantar flexion contractions immediately before and after either: (a) 3 × 15 eccentric heel drops or (b) 10-min rest. There was a significant time-by-session interaction for free tendon length and strain for all loading conditions ( P < 0.05). Pairwise comparisons revealed a significant increase in free tendon length and strain at all contraction intensities after eccentric exercise ( P < 0.05). There was no significant time-by-session interaction for the gastrocnemii (medial or lateral) aponeurosis or tendon for any of the measured parameters. Immediate changes in Achilles tendon mechanical properties were specific to the free tendon and consistent with changes due to mechanical creep. These findings suggest that the mechanical properties of the free tendon may be more vulnerable to change with exercise compared with the gastrocnemii aponeurosis or tendon. [ABSTRACT FROM AUTHOR]

Slackline training (balancing on nylon ribbons) has been shown to improve neuromuscular performance in children and adults. Comparable studies in seniors are lacking. Thus, 32 seniors were randomly assigned [strata: age, gender, physical activity ( PA)] to an intervention [ INT; n = 16, age: 65 ± 4 years, PA: 9 ± 5 h/week] or control [ CON, n = 16, age: 63 ± 4 years, PA: 8 ± 4 h/week] group. Slackline training was given for 6 weeks (3 times per week, attendance 97%). Static and slackline standing balance performance, force development, and maximal strength of the ankle muscles were assessed before and after slackline training. Muscle activity (lower limb and trunk) was recorded during balance testing. Moderate to large group × time interactions (0.02 < P < 0.04, 0.11 < ηp2 < 0.17) in favor of INT were found for slackline standing times ( INT: left, +278%, P = 0.02; right, +328%, P = 0.03; tandem, +94%, P = 0.007) and muscle activity during single-limb slackline standing [ INT: right: rectus abdominis ( RA), P = 0.003, −15%; multifidus ( MF), P = 0.01, −15%; left: tibialis anterior ( TIB), P = 0.03, −12%; soleus ( SOL), P = 0.006, −18%; RA, P = 0.04, −11%; MF, P = 0.01, −16%; gastrocnemius medialis ( GM), P = 0.02, −19%]. Static balance performance, ankle strength, and power were not affected. Slackline training induced large task-specific improvements of slackline standing performance accompanied with reductions of lower limb and trunk muscle activity. Transfer effects to static balance and strength measures seem limited. [ABSTRACT FROM AUTHOR]

Ankle joint range of motion (ROM) is notably influenced by the position of the hip joint. However, this result remains unexplained. Thus, the aim of this study was to test if the ankle passive torque and gastrocnemius muscle tension are affected by the hip and the head positions. The torque and the muscle shear elastic modulus (measured by elastography to estimate muscle tension) were collected in nine participants during passive ankle dorsiflexions performed in four conditions (by combining hip flexion at 90 or 150°, and head flexed or neutral). Ankle maximum dorsiflexion angle significantly decreased by flexing the hip from 150 to 90° (P < 0.001; mean difference 17.7 ± 2.5°), but no effect of the head position was observed (P > 0.05). Maximal passive torque and shear elastic modulus were higher with the hip flexed at 90° (P < 0.001). During submaximal ROM, no effects of the head and hip positioning (P > 0.05) were found for both torque and shear elastic modulus at a given common ankle angle among conditions. Shifts in maximal ankle angle due to hip angle manipulation are not related neither to changes in passive torque nor tension of the gastrocnemius. Further studies should be addressed to better understand the functional role of peripheral nerves and fasciae in the ankle ROM limits. [ABSTRACT FROM AUTHOR]

The article offers information on the study of impact of dynamic stretching on the neuromechanical and sensorimotor performance of the ankle plantarflexors. It mentions the study use a crossover design to compare joint mechanical properties and proprioception outcomes in 18 healthy subjects who received slow and fast dynamic stretches to the plantarflexor muscles and concluded harmful effect of dynamic stretching on the performance of the ankle plantarflexors.