Abstract Background Knee injuries involving the anterior cruciate ligament (ACL) are often treated through surgical care to restore knee joint stability. Despite surgical treatment, there is evidence of altered biomechanical gait characteristics for short-, mid-, and even long-term post ACL reconstruction (ACLR). Objective In this systematic review with meta-analysis, we aimed to analyze lower extremity joint kinematics and kinetics recorded during walking in individuals with ACLR and determine the time course of recovery of gait biomechanics following ACLR. Methods Five electronic databases (Scopus, PubMed, EMBASE, Physiotherapy Evidence Database (PEDro), Cochrane Central Register of Controlled Trials [CENTRAL]) were systematically searched for articles potentially eligible for inclusion from inception until January 2026. A PECOS (Participants: ACLR individuals aged ≥ 18; Exposure: ACL surgery; Comparators: healthy controls; Outcomes: lower limb kinematics and kinetics during the walking stance phase; and Study design: case control studies, case series, cross-sectional studies, randomized controlled trials [baseline], cohort studies) approach was applied to define inclusion and exclusion criteria. Using cross-sectional studies, gait biomechanics were assessed short- (0–<6 months), mid- (≥ 6–12 months), and long-term (≥ 12 months) post-surgery in ACLR patients versus healthy controls. Gait biomechanics assessed during the stance phase were extracted from the included articles. Between-group standardized mean differences (SMD) with 95% confidence intervals (CI) were computed using a random-effects model to elucidate the gait biomechanical differences between ACLR patients and healthy controls. The modified version of the Downs and Black checklist was used to assess the methodological quality of the included studies. Results The initial search identified 3199 hits and according to a priori defined in-/exclusion criteria, 31 cross-sectional studies with males and females aged 17–55 years were eligible to be included. The mean methodological quality of all included studies was moderate (Downs and Black checklist score: 68%). Based on outcomes from 17 studies, lower peak knee flexion angles were noted during the stance phase of walking in ACLR patients compared to controls (small SMD=-0.50, 95% CI -0.77 to -0.22, p = 0.0004, I2 = 79%) which could even be found ≥ 12 months post-surgery (11 studies: small SMD=-0.49, 95% CI -0.84 to -0.15, p = 0.005, I2 = 83%). Up until six months post-surgery, lower peak knee adduction angles (four studies: moderate SMD=-0.56, 95% CI -0.96 to -0.16, p = 0.006, I2 = 47%) were observed in ACLR patients. Regarding kinetics, irrespective of the time point post ACLR, the peak knee flexor joint moments (11 studies: moderate SMD=-0.57, 95% CI -0.90 to -0.25, p = 0.0005, I2 = 69%) were lower in the ACLR group compared to controls. Conclusions After ACLR, the observed reduction in peak knee flexion angle suggests a walking pattern with a straighter knee, or a less erect gait posture, which can persist for ≥ 12 months post surgery. The lower sagittal plane knee moments suggest a less dynamic gait, characterized by reduced muscular demand. The small deviations in gait biomechanics from normal are lasting but inconsistent between studies. While associated with long-term outcomes like post-traumatic osteoarthritis, the direct clinical relevance of these specific gait changes requires further study.

During human movement, the neuromuscular system continuously adapts to varying and differently predictable demands. Practicing with sequences of known and unknown types of muscle contractions could train force control of muscle. We compared the acute effects of practicing with eccentric and concentric quadriceps muscle contractions at different velocities with known and unknown sequences, on knee extension torque, torque steadiness, and joint position sense in healthy young adults. Nineteen physically active young men practiced unknown and known muscle loading conditions on an isokinetic dynamometer, comprising eccentric and concentric contractions at different velocities in randomized and predefined sequences (16 contractions per condition). Joint position sense, maximal voluntary isometric contraction torque, and torque steadiness before and after practices, as well as mechanical work during the practice contractions were measured. Maximal voluntary isometric contraction torque and joint position sense remained unchanged in both practice conditions, while torque steadiness variable error obtained at 70

IntroductionDynamic knee valgus is linked to reduced hip abduction strength, a critical factor in knee stability during unilateral movements. While interventions to reduce dynamic knee valgus often use traditional hip abduction training, many neglect the eccentric function of hip abductors, essential for controlling femoral medial translation. This pilot study compared the effects of a four-week-long eccentric vs. concentric hip abduction training on hip abduction torque, countermovement jump performance, dynamic knee valgus measured during one-legged jumping and drop landing, and determined if reductions in dynamic knee valgus correlated with increases in hip abduction torque and countermovement jump performance.Materials and methodsAsymptomatic, physically active female college students (n = 20, 21.3 ± 2.51 years) with dynamic knee valgus were randomized to either eccentric or concentric hip abduction strength training. Testing included maximum hip abduction torque on an isokinetic dynamometer, single-leg countermovement jumps, and single-leg drop landings analyzed with 3D motion tracking. Participants trained three times per week for four weeks, performing four sets of 10 maximal effort repetitions.ResultsThe two groups did not differ at baseline in any outcomes (all p > 0.05). Eccentric hip abduction torque improved over time (F = 39.7, p < 0.001) without a group-by-time interaction. Dynamic knee valgus decreased during single-leg countermovement jumps (time main effect: F = 33.5, p < 0.05) and single-leg drop landings (time main effect: F = 14.8, p < 0.05). The reductions in dynamic knee valgus, measured during single-leg countermovement jumps, were greater (p < 0.05) after eccentric vs. concentric training (group by time interaction: F = 5.57, p < 0.05). Countermovement jump improved similarly in the two groups (time main effect: F = 5.1, p < 0.05), without group by time interaction. Improvements in hip abduction maximal torque and countermovement jump performance, and changes in dynamic knee valgus outcomes did not correlate (p > 0.05).ConclusionsHigh-intensity eccentric versus concentric hip abductor strength training was superior in dynamic knee valgus improvement measured during single-leg countermovement jump but not during drop landings in asymptomatic young women, while both training modalities improved single leg countermovement jump performance.

Dynamic knee valgus (DKV) is commonly used in functional screening related to anterior cruciate ligament (ACL) injury risk; however, assessments often rely on peak valgus alone despite the combined influence of knee valgus and flexion on knee loading. This study compared knee kinematics and vertical ground reaction forces (GRFs) between single-leg landing (SLL) and single-leg countermovement jump (SL-CMJ), focusing on peak knee valgus, knee flexion at peak valgus, valgus angular velocity, knee flexion-normalized valgus, and GRFs. Physically active, asymptomatic female participants (n = 30) performed both the SLL and SL-CMJ tasks. Knee kinematics and GRFs were recorded using motion-tracking sensors and a force platform. Peak knee valgus did not differ between tasks. Compared with SL-CMJ, SLL produced 24% less knee flexion at peak valgus, 17% greater knee flexion-normalized valgus, 254% higher valgus angular velocity, and 124% higher GRFs (all p < 0.05). These findings demonstrate task-dependent differences in landing mechanics that are not captured by peak knee valgus alone. Assessing knee valgus together with knee flexion and its temporal development may provide a more comprehensive characterization of potentially relevant knee-loading mechanics. The high valgus angular velocities observed during SLL may also inform the development of velocity-specific neuromuscular training strategies.

(1) Background: Flexible flatfoot is characterized by medial arch collapse, leading to musculoskeletal impairments. We examined the effects of single-arch foot orthosis (SFO) and dual-arch foot orthosis (DFO) on arch height, kinematics, and kinetics in young females during walking and jogging. (2) Methods: Healthy females (n = 19) with flexible flatfoot were tested under three conditions: regular shoes, SFO, and DFO. Motion capture and a 3D force plate gathered biomechanical data. We also used a high-speed dual fluoroscopic imaging system (DFIS) to assess dynamic foot morphology. Outcomes included normalized truncated navicular height, medial arch angle, angles and moments at the metatarsophalangeal, subtalar, ankle, knee, and hip joints. (3) Results: Both types of orthoses improved the normalized navicular height and reduced the medial arch angle, with DFO vs. SFO showing greater effects (p < 0.001). DFO vs. SFO was also more effective in limiting the range of motion (ROM) of the metatarsophalangeal joint and dorsiflexion (p < 0.001). Additionally, DFO reduced the ankle range of motion and the maximum knee flexion during walking. Both orthoses reduced subtalar plantarflexion moments during stance (p < 0.001) and modulated ankle plantarflexion moments throughout different phases of gait. DFO uniquely enhanced metatarsophalangeal plantarflexion moments during jogging (p < 0.001). (4) Conclusions: Dual vs. single transverse arch foot orthosis is more effective in improving gait biomechanics in females with flexible flatfoot. Longitudinal studies are needed to confirm these benefits.

Athletes often use cold water immersion (CWI) to enhance responses to exercise and speed recovery. Much less is known about practice and environmental characteristics, perceived benefits and risks, and adverse experiences of CWI in healthy adults in a recreation setting and if these factors differ by sex. Members of the CWI communities completed a 118-item survey. Caucasian males (n = 66, age: 46y) and females (n = 27, age: 49y) were healthy, highly educated, and physically active. Primary aim to pursue CWI was to improve general health, mental health, and fitness. Participants engaged in CWI 1-3 times per week (55%), with sessions lasting either 5 min (40%) or 6-40 min (60%) in water temperatures ranging from 5-15 degrees C (90%). Men reported higher pain during CWI than women; however, participants generally rated the perceived risks associated with CWI as very low and reported no adverse events. The current data expands existing laboratory data in healthy middle-aged adults using CWI recreationally and suggest that these individuals can continue to use CWI safely for improved physical and mental function.

Vision plays a fundamental role in the control of human locomotion, including walking gait. Given that side-dominance is associated with differences in motor control, the present study aimed to determine if patches obscuring half of the visual field affect left- and right-side dominant individuals’ gait kinematics and accompanying leg muscle activation differently. Healthy right- (n = 15, age = 28.2 ± 5.5 years) and left-side (n = 9, age = 27.9 ± 5.8 years) dominant participants performed 10 min of walking trials on a treadmill at a self-selected speed with 5 min of rest between three randomized trials, i.e., wearing clear glasses or glasses with left-or right half-field eye patching. In addition to a set of spatiotemporal and kinematic gait parameters, the average activity during the separated gait cycle phases, and the start and end of muscle activation in % of the gait cycle were calculated from five muscles in three muscle groups. Our results indicate that gait kinematics of left- and right-side dominant participants were similar both in their dominant and non-dominant legs, regardless of half-field eye patching condition. On the other hand, inter-group differences were found in selected kinematic variables. For instance, in addition to larger but less variable step width, our results suggest larger ankle and knee ROM in right- vs. left-sided participants. Furthermore, medial gastrocnemius and biceps femoris muscle activation showed selected differences at certain phases of the gait cycle between participants’ dominant and non-dominant legs. However, it was also unaffected by the half-field eye patching condition. Moreover, the endpoint of medial gastrocnemius activation was affected by side-dominance, i.e., its activation ended earlier in the non-dominant leg of right- as compared to left-side dominant participants. Our results suggest no major differences in walking gait kinematics and accompanying muscle activation between half-field eye patching conditions in healthy adults; nevertheless, side-dominance may affect biomechanical and neuromuscular control strategies during walking gait.

Background: Comparative efficacy of rehabilitation interventions in persons with acute ischemic stroke (PwS) is limited. This randomized trial assessed the immediate and lasting effects of five interventions on clinical and mobility outcomes in 75 PwS. Methods: Five days after stroke, 75 PwS were randomized into five groups: physical therapy (CON, standard care, once daily); walking with a soft robotic exoskeleton (ROB, once daily); agility exergaming once (EXE1, once daily) or twice daily (EXE2, twice daily); and combined EXE1+ROB in two daily sessions. Interventions were performed 5 days per week for 3 weeks. Outcomes were assessed at baseline, post-intervention, and after 5 weeks of detraining. Results: Modified Rankin Scale (primary outcome) and Barthel Index showed no changes. EXE1, EXE2, ROB, and EXE1+ROB outperformed standard care (CON) in five secondary outcomes (Berg balance scale, 10m walking speed, 6-min walk test with/without robot, standing balance), with effects sustained after 5 weeks. Dose effects (EXE1 vs. EXE2) were minimal, while EXE1+ROB showed additive effects in 6-min walk tests. Conclusions: These novel comparative data expand evidence-based options for therapists to design individualized rehabilitation plans for PwS. Further confirmation is needed.

Background/Objectives: As aging leads to a decline in muscle mass, strength, and functional capacity, identifying effective, low-risk interventions for older adults is essential. Blood flow restriction training (BFRT) has gained recognition as a potential substitute for traditional high-load resistance training, offering comparable benefits with reduced mechanical stress. This scoping review explores current BFRT protocols—specifically cuff pressure, training frequency, and duration—and their impact on muscular strength, hypertrophy, and functional capabilities among healthy elderly individuals. Methods: Following PRISMA-ScR and Arksey and O’Malley’s framework, six databases were searched (2010–2024), yielding 13 eligible studies. Data were charted for BFRT parameters, training regimens, and outcomes related to strength, muscle size, and functionality. Risk of bias was assessed using Cochrane guidelines. Results: Low-load BFRT (20–40% 1RM), applied 2–4 times weekly for 6–12 weeks, significantly improved muscle strength, hypertrophy (e.g., quadriceps CSA), and functional performance (e.g., TUG, 6MWT). Cuff pressures ranged from 50 to 80% arterial occlusion pressure (AOP) for the lower limbs and 30–50% above systolic pressure for the upper limbs. Wider cuffs enhanced safety and comfort. BFRT demonstrated comparable or superior outcomes to conventional training in most studies, with minimal adverse effects reported. Conclusions: The existing evidence suggests that BFRT may be a promising intervention for improving muscle health and functionality in older adults; however, future research should focus on standardizing protocols, long-term outcomes, and tailored guidelines to optimize safety and efficacy.

BACKGROUND:Stroke incidence rises with age. A stroke can severely affect walking ability, requiring therapy. Robot-assisted walking therapy (ROB) has been advocated as one form of walking rehabilitation in stroke patients. However, its comparative efficacy remains controversial and three-group comparisons are scant. We compared the effects of ROB, walking training therapy without a robot (WTT) and standard treatment therapy (STT) on clinical and mobility outcomes in acute ischemic stroke patients. METHODS:Individuals (n = 45, 71 % males, age 64.4y ±6.34), who have recently experienced an ischemic stroke, were randomized to ROB, WTT or STT. Clinical and mobility outcomes were assessed before and after each intervention (3 weeks, 5 sessions/week) and after 5 weeks of no-intervention follow-up. RESULTS:Outcomes did not differ between groups at baseline (p > 0.05). Modified Rankin Scale (primary outcome), improved (p < 0.05) after ROB and WTT vs. STT. These improvements were retained relative to baseline (p < 0.05) after follow-up. Barthel index, Berg Balance Scale, 10-m walking speed, the distance while walking with and without the robot for six minutes, and center pressure velocity in standing improved most after ROB (all p < 0.001), exceeding the changes after WTT which in turn were greater than the changes after STT (p ≤ 0.040). CONCLUSION:Older adults shortly after an ischemic stroke can quickly learn to walk with a soft robot and retain substantial clinical and mobility improvements at follow-up.

Purpose:Contribution of the gastrocnemii muscles to ankle moment is influenced by the knee joint position because they span the knee and the ankle joint as well. However, limited information is available on the effect of knee joint position on soleus activation under dynamic plantarflexion, hence the aim of this study was to investigate if soleus have a compensatory strategy in fascicle behavior or EMG activity during knee flexed plantarflexion in order to reduce the magnitude of the decrement in ankle moment. Equipment and methods:Isokinetic dynamometry with EMG and ultrasound measurements was used to estimate medial gastrocnemius and soleus behavior during knee flexed and extended plantarflexions using three angular velocities. Seventeen healthy males were participated in this study. Results:Flexed knee plantarflexions resulted in lower peak ankle moments at all ankle angular velocities by 18% (P = 0.1062) at 30°∙s-1, 44% (P < 0.001) at 60°∙s-1 and by 18% (P = 0.0001) at 120°∙s-1. Soleus showed significantly higher EMG activity during knee flexed plantarflexion at 30°∙s-1 (P = 0.0094) and 60°∙s-1 (P = 0.0142). The magnitude of mean shortening of the medial gastrocnemius and soleus show statistically significant difference between knee flexed and knee extended plantarflexion at any contraction velocity. Conclusions:Soleus may perform a compensatory EMG activity in knee flexed plantarflexions possibly to counteract the reduced contribution of gastrocnemius to ankle moment at low angular velocity contractions.

Biomechanics (ISSN 2673-7078) is an international, peer-reviewed, open access journal covering all aspects of biomechanics, which can be described as the application of principles and methods of mechanics to the quantitative study of biological systems [...]

Abstract Background Beam walking is a new test to estimate dynamic balance. We characterized dynamic balance measured by the distance walked on beams of different widths in five age groups of healthy adults (20, 30, 40, 50, 60 years) and individuals with neurological conditions (i.e., Parkinson, multiple sclerosis, stroke, age: 66.9 years) and determined if beam walking distance predicted prospective falls over 12 months. Methods Individuals with (n = 97) and without neurological conditions (n = 99, healthy adults, age 20–60) participated in this prospective longitudinal study. Falls analyses over 12 months were conducted. The summed distance walked under single (walking only) and dual-task conditions (walking and serial subtraction by 7 between 300 to 900) on three beams (4, 8, and 12-cm wide) was used in the analyses. Additional functional tests comprised grip strength and the Short Physical Performance Battery. Results Beam walking distance was unaffected on the 12-cm-wide beam in the healthy adult groups. The distance walked on the 8-cm-wide beam decreased by 0.34 m in the 20-year-old group. This reduction was ~ 3 × greater, 1.1 m, in the 60-year-old group. In patients, beam walking distances decreased sharply by 0.8 m on the 8 versus 12 cm beam and by additional 1.6 m on the 4 versus 8 cm beam. Beam walking distance under single and dual-task conditions was linearly but weakly associated with age (R2 = 0.21 for single task, R2 = 0.27 for dual-task). Age, disease, and beam width affected distance walked on the beam. Beam walking distance predicted future falls in the combined population of healthy adults and patients with neurological conditions. Based on receiver operating characteristic curve analyses using data from the entire study population, walking ~ 8.0 of the 12 m maximum on low-lying beams predicted future fallers with reasonable accuracy. Conclusion Balance beam walking is a new but worthwhile measure of dynamic balance to predict falls in the combined population of healthy adults and patients with neurological conditions. Future studies are needed to evaluate the predictive capability of beam walking separately in more homogenous populations. Clinical Trial Registration Number NCT03532984.

The optimal prescription and precise recommendations of resistance training volume for older adults is unclear in the current literature. In addition, the interactions between resistance training volume and program duration as well as physical health status remain to be determined when assessing physical function, muscle size and hypertrophy and muscle strength adaptations in older adults. This study aimed to determine which resistance training volume is the most effective in improving physical function, lean body mass, lower-limb muscle hypertrophy and strength in older adults. Additionally, we examined whether effects were moderated by intervention duration (i.e. short term, < 20 weeks; medium-to-long term, ≥ 20 weeks) and physical health status (i.e. physically healthy, physically impaired, mixed physically healthy and physically impaired; PROSPERO identifier: CRD42023413209). CINAHL, Embase, LILACS, PubMed, Scielo, SPORTDiscus and Web of Science databases were searched up to April 2023. Eligible randomised trials examined the effects of supervised resistance training in older adults (i.e. ≥ 60 years). Resistance training programs were categorised as low (LVRT), moderate (MVRT) and high volume (HVRT) on the basis of terciles of prescribed weekly resistance training volume (i.e. product of frequency, number of exercises and number of sets) for full- and lower-body training. The primary outcomes for this review were physical function measured by fast walking speed, timed up and go and 6-min walking tests; lean body mass and lower-body muscle hypertrophy; and lower-body muscle strength measured by knee extension and leg press one-repetition maximum (1-RM), isometric muscle strength and isokinetic torque. A random-effects network meta-analysis was undertaken to examine the effects of different resistance training volumes on the outcomes of interest. We included a total of 161 articles describing 151 trials (n = 6306). LVRT was the most effective for improving timed up and go [− 1.20 standardised mean difference (SMD), 95

Kettlebell as a sport has gained recognition worldwide. We characterized the physiological responses induced by a simulated kettlebell competition routine in experienced kettlebell athletes (n = 26) in a two-group, pre-post plus short-term follow-up, non-randomized experiment. The experimental group (EXP) included 13 kettlebell athletes, while the control group (CON) consisted of 13 individuals with prior recreational exposure to kettlebell activities. EXP performed a 10-minute-long, long-cycle kettlebell routine, whereas CON engaged in seated rest. Cardiovascular and neuromuscular outcomes were measured at rest, after warm-up, during exercise, at 0 (immediately post), 5 and 15 min into recovery. Group-by-time interactions revealed that the 10-minute-long, long-cycle kettlebell routine increased (P < 0.05) the levels of all outcomes (e.g. heart rate, blood pressure, blood lactate) (range of effect sizes: -0.9-8.9) with many outcomes remaining well above baseline at 5 and 15 min into recovery. A notable exception was a lack of change in maximal squat strength. Kettlebell experience and mass correlated with changes in oxygen uptake (Delta VO2) and in ventilation (Delta VT) (r = -0.70, 0.64, -0.87, and 0.73, respectively, P < 0.05) in EXP. Kettlebell routine evoked significant changes in all physiological variables (respiratory and cardiovascular), out of which the heart rate (HR), diastolic blood pressure (DBP), rate pressure product (RPP), and blood lactate (BL) outlasted the routine for at least 15 min. Future studies should longitudinally examine physiological responses to kettlebell training throughout a season. Long-cycle kettlebell routine adds to the repertoire of evidence-based exercise options for high-intensity exercise.

We determined the effects of knee joint position on the relationship between maximal voluntary contraction (MVC) isometric plantar flexor torque and architectural properties of the plantar flexors measured at rest in healthy young adults. We obtained 3-D reconstructed muscle architecture data of the right plantar flexor muscles of nine physically active males using T1 and DTI MRI sequences with the knee in ∼5° flexion and at rest. Muscle volume, fascicle length, pennation angle, and physiological cross-sectional area were estimated for the medial and lateral gastrocnemius and the soleus muscle. MVC isometric plantar flexor torque was assessed on a dynamometer with the knee flexed and extended. MVC isometric plantar flexor torque was 59 % lower when performed with the knee flexed (93.1 ± 22.3 N∙m) vs. extended (154.4 ± 37.8 N∙m). Medial (r = 0.70, p = 0.026) and lateral gastrocnemius (r = 0.49, p = 0.048), total soleus (r = 0.79, p = 0.01), and total triceps suræ muscle volume (r = 0.77, p = 0.012) correlated with MVC isometric plantarflexion torque produced with the knee extended. However, only total soleus (r = 0.64, p = 0.028) and triceps suræ volume (r = 0.64, p = 0.031) correlated with MVC isometric plantar flexor torque produced with the knee flexed. Only the total soleus (r = 0.66, p = 0.038) and triceps suræ physiological cross-sectional area (r = 0.55, p = 0.049) correlated with MVC isometric plantar flexor torque performed with knee extended. The data suggest that knee joint position affects torque-size relationship in the gastrocnemius muscles. Additionally, it appears that the total soleus and triceps suræ muscle volumes association with MVC isometric plantar flexor torque is larger than the total physiological cross-sectional area of the triceps suræ. In conclusion, the data suggest that knee joint position affects torque-size relationship in the gastrocnemii but not in the soleus muscle.

Background: Headache is one of the leading causes of disability in the world. Neck proprioception, pain, and postural control are interconnected in both healthy individuals and those with chronic neck pain. This study examines the effects of proprioceptive training using a gaze direction recognition task on postural stability and pain in cervicogenic headache patients. Methods: Patients with cervicogenic headache (n = 34, age: 35–49 y) were randomized into a control group (CON), receiving only selected physical therapy rehabilitation or to an experimental group (EXP), performing proprioceptive training using a gaze direction recognition task plus selected physical therapy rehabilitation. Both programs consisted of 24, 60 min long sessions over 8 weeks. Postural stability was assessed by the modified clinical test of sensory integration of balance (mCTSIB) and a center of pressure test (COP) using the HUMAC balance system. Neck pain was assessed by a visual analog scale. Results: In all six tests, there was a time main effect (p < 0.001). In three of the six tests, there were group by time interactions so that EXP vs. CON improved more in postural stability measured while standing on foam with eyes closed normalized to population norms, COP velocity, and headache (all p ≤ 0.006). There was an association between the percent changes in standing on foam with eyes closed normalized to population norms and percent changes in COP velocity (r = 0.48, p = 0.004, n = 34) and between percent changes in COP velocity and percent changes in headache (r = 0.44, p = 0.008, n = 34). Conclusions: While we did not examine the underlying mechanisms, proprioceptive training in the form of a gaze direction recognition task can improve selected measures of postural stability, standing balance, and pain in cervicogenic headache patients.

Mental fatigue can affect cognitive function and interfere with motor performance. We examined if mental fatigue affected gait through age-specific modulation of wavelet-based time-frequency intermuscular beta-band coherence in muscles while walking on a treadmill at 1.2 m·s-1. The Psychomotor Vigilance Task, and the AX-Continuous Performance and the Stroop tests were used to induce mental fatigue in groups of healthy young and older participants. Mental fatigue reduced stance time, stride length, and marginally step width and increased cadence, stride length and stance time variability. In older compared with young participants before the induction of mental fatigue, wavelet-based time-frequency intermuscular beta-band coherence measured during walking was lower in the tibialis-peroneus and tibialis-gastrocnemius muscle pairs in specific phases of the gait cycle. In both age groups, after induction of mental fatigue, selected clusters of wavelet-based time-frequency intermuscular beta-band coherence measured during walking increased in the biceps-semitendinosus, rectus-vastus, tibialis-peroneus, gastrocnemius-soleus, and tibialis-gastrocnemius muscle pairs. In conclusion, we observed that while old age might weaken oscillatory coupling between selected ankle muscle pairs during gait, reflecting a certain level of impairment in the descending drive to these muscles, wavelet-based time-frequency intermuscular beta-band coherence measured during gait after mental fatigue migth increase independent of age.

Background The similarity between movement patterns and force-vector specificity of training exercises and the target movement will likely result in the greatest transfer of the practiced skills and physical abilities to the intended sports skill performance. Therefore, this review aimed to investigate whether specific adaptations in athletic performance would be observed following direction specific exercise training. Methodology The literature search was performed in PubMed, Web of Science, and MEDLINE. Studies comparing acute (post-activation potentiation enhancement) and short-term (>2 weeks) effects of horizontally vs. vertically oriented resistance and plyometric training on athletic performance of recreationally active participants of either sex were included. The effect sizes were determined using a robust variance estimation random-effects model and were reported as Hedge’s g. Results Twenty-two studies were included. For acute studies (n = 4), a small non-significant effect favoring horizontal training (HT) for sprint performance improvements (g = −0.19, p = 0.17) was evident. For short-term studies (n = 18), the results showed non-significant, small to large differences between HT and vertical training (VT) in pooled vertical and horizontal jump improvements (g = 0.06, p = 0.67), vertical (g = 0.21, p = 0.17) and horizontal jump (g = −0.15, p = 0.40), pooled vertical and horizontal maximal strength (g = 0.27, p = 0.42), horizontal (g = −0.83, p = 0.16) and vertical maximal strength (g = 0.78, p = 0.28), pooled short and medium distance sprint (g = −0.23, p = 0.16), short (g = −0.33 [−0.85, 0.19], p = 0.19) and medium (g = −0.12 [−0.37, 0.13], p = 0.28) distance sprint, and COD speed and maneuverability (g = −0.45, p = 0.26). Conclusions HT and VT were both equally effective in improving vertically and horizontally athletic performance, potentially refuting the theory of directional specificity of training on athletic performance outcomes.

Knee joint position influences ankle torque, but it is unclear whether the soleus compensates to counteract the reductions in gastrocnemius output during knee-flexed versus knee-extended plantarflexions. Therefore, the purpose of this study was to determine the effects of knee joint position and plantarflexion contraction velocity on ankle plantarflexion torque and electromyography activity of the medial gastrocnemius and soleus in healthy young adults. Healthy male participants (n=30) performed concentric plantar flexions in a custombuilt dynamometer from 15 degrees dorsiflexion to 30 degrees plantarflexion at gradually increasing velocities during each contraction at 30, 60, 120, 180, and 210 degrees s-1 in a supine position with the knee fully extended and while kneeling with the knee fixed in 90 degrees flexion. Two 16-channel linear electromyographic (EMG) arrays were placed over the medial gastrocnemius and soleus muscles. Plantarflexion torque during flexed-knee versus extended-knee plantarflexions was 31% lower (P=0.002) averaged across the five contraction velocities. The overall EMG activity of the medial gastrocnemius was 35% lower (P=0.002) during knee-flexed versus knee-extended plantarflexions. In the first half of plantarflexions at slower contractions, soleus EMG activity was 15% and 28% higher (both P=0.002) in knee-flexed versus knee-extended plantarflexion, respectively. We conclude that knee position affects medial gastrocnemius and soleus activation during dynamic plantarflexion, with plantarflexion torque being smaller in the knee-flexed versus knee-extended position. However, we found no evidence that changes in soleus activation would compensate for the decrease in medial gastrocnemius activation.