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The primary objective of the study was to evaluate the risk of lower-extremity injury during landing, after catching a basketball in the air for a rebound or a steal. A total of 32 (15 females and 17 males) recreational basketball players were asked to perform 4 different arm-reaching movements during the flight phase: no reaching, left (LAR), right (RAR), and bilateral (BAR) arm reaching. Knee and hip flexion and abduction angles at initial ground contact, peak ground reaction force within 100 milliseconds after contact, and peak moments for the hip and knee joints were analyzed. LAR, RAR, and BAR showed significantly smaller peak hip and knee flexion angles, while LAR demonstrated a significant increase in the knee’s peak abduction angle. Furthermore, the peak abduction moments of LAR were significantly increased in both males and females. Aerial basketball catching movements resulted in stiffer leg joints and larger knee abduction during landing, which was a potential factor in increasing the risk of lower-limb injury upon landing. It is recommended to include a softer landing technique and implement a training program for enhancing knee joint stabilization in the frontal plane.

Patients with peripheral artery disease (PAD) often experience leg muscle damage, leading to noticeable walking difficulties. Using ankle foot orthosis (AFO) may enhance gait by supporting weak muscles. This study examined whether wearing AFOs improved the spatiotemporal gait characteristics of patients with PAD to be closer to those of healthy individuals, both from its first use and after a 3-month intervention. Spatiotemporal parameters were calculated from the kinematics of 26 patients with PAD captured in a biomechanics lab. Subjects walked with and without AFOs before and following a 3-month AFO intervention on a crossover basis. The immediate intervention group wore AFOs for 3 months (intervention) before switching to their control shoes (control), while the delayed intervention group followed the reverse sequence. Means and standard deviations (variability) for step width, length, time, and velocity were compared using separate linear repeated measures models. The models included group (immediate vs delayed intervention), time (before vs after intervention or baseline vs 3 mo), and condition (non-AFO vs AFO) as factors of comparison, in addition to interactions, if significant. A 3-month AFO intervention enhanced the temporal gait parameters and reduced gait variability. The mean and variability of temporal gait parameters were sensitive enough to determine whether patients walked more like healthy individuals after a 3-month AFO intervention. This may decrease fall risk and promote more efficient walking patterns in patients with PAD. The long-term benefits and adherence to AFOs and other assistive devices need further study.

When carrying out a motor task, the direction of the performer’s attentional focus can affect mechanical output and muscle activation. Cortical excitability increases with the observation of motor skills. However, it is unknown if this effect can be additive to that resulting from an internal attentional focus during resistance exercise. A crossover-study design was employed to examine the acute effects of combining mirror self-motor observation (MO) and internally focused verbal instructions on mechanical output and muscle activation during isokinetic concentric knee-extension exercise. Ten participants were tested in 2 different conditions: verbal alone and verbal + MO-mirror. The combination of verbal + MO-mirror attenuated the decrease in torque output in response to 6 sets of 10 isokinetic contractions (P = .043). Interestingly, this effect was paired by a lower-level antagonist/agonist coactivation with the verbal + MO-mirror condition (P = .031). No other differences between conditions were noted. Taken together, these results suggest that the combination of both cueing modalities elicits a more effective contraction strategy during knee-extension exercise. Ultimately, this provides preliminary evidence of better motor performance and heightened fatigue resistance in response to isokinetic exercise.

It is unknown if forward trunk lean during single-limb landing influences the Achilles tendon force (ATF). This study examined the effect of forward trunk lean during single-limb landing on the ATF in physically active females. Thirty physically active females (23.7 [3.6] y) performed 5 landing trials (0.25 m) using self-selected and forward trunk lean strategies. Dependent variables included peak ATF; average ATF development rate; and sagittal trunk, hip, knee, and ankle angles and moments at the time of peak ATF. The increased forward trunk lean (mean difference (MD) = 14.1°; 95% CI, 11.0 to 17.2; P < .001) caused a decrease in peak ATF (MD = −3.5 N/kg; 95% CI, −5.8 to −1.2; P = .004) and ankle plantar flexion moment (MD = −0.2 N·m/kg; 95% CI, −0.4 to −0.1; P = .002). In contrast, forward trunk lean resulted in greater hip (MD = 15.2°; 95% CI, 11.9 to 18.4; P < .001) and knee flexion (MD = 7.7°; 95% CI , 4.7 to 10.7; P < .001) angles, and hip extension moment (MD = 0.3 N·m/kg; 95% CI, 0.1 to 0.5; P = .002). Forward trunk lean changes predicted peak ATF changes (r = .33, P = .04). Sagittal trunk posture influences the ATF in physically active females during single-limb landing and may effectively alter loading in patients recovering from Achilles tendinopathy.

The calf raise test (CRT) is commonly used to assess triceps surae muscle-tendon unit function. Often, a metronome set to 60 beats/min (30 repetitions/min) is used to set the cadence of calf raise repetitions, but studies report using cadences ranging from 30 to 120 beats/min. We investigated the effect of cadence on CRT outcomes, accounting for the potential confounders of sex, age, body mass index, and physical activity. Thirty-six healthy individuals (50% female) performed single-leg calf raise repetitions to volitional exhaustion in 3 randomized cadence conditions, 7 days apart: 30, 60, and 120 beats/min. Repetitions, total vertical displacement, total work, peak height, and peak power were recorded using the validated Calf Raise application. Cadence significantly affected all CRT outcomes (P ≤ .008), except repetitions (P = .200). Post hoc analysis revealed 60 beats/min resulted in significantly greater total vertical displacement and work than 30 and 120 beats/min. Peak height was greater at 60 and 120 than 30 beats/min, and peak power was greater at 120 beats/min. Males generated greater work and peak power (P ≤ .001), whereas individuals with greater body mass index completed less repetitions (P = .008), achieved lower total vertical displacements (P = .003), and generated greater peak power (P = .005). CRT cadence is important to consider when interpreting CRT outcomes and comparing data between studies.

In many sports, practitioners must reach their maximal jump height (h _max) under time constraints. This requires a reduction of the countermovement depth and so of the push-off distance (h _PO). The purpose of this study was to investigate how h _PO influences force–velocity (F–v) profiles ( ${\overline{F}}_0$ , ${\overline{v}}_0$ , ${\overline{\mathrm{P}}}_{\max }$ , and S _Fv ) and performance. Eleven participants (age: 26 [5] y, height: 175.6 [11.2] cm, mass: 76 [15] kg; squat 1RM: 129 [34] kg) performed maximal countermovement jumps. Kinetic and kinematic measurements were used to assess individual F–v profiles for 3 different h _PO conditions (h _PO-SMALL, h _PO-MEDIUM, h _PO-LARGE) from countermovement jumps performed under different load conditions (bodyweight [BW], BW + 8 kg, BW + 17 kg, BW + 40%1RM, BW + 70%1RM). Results indicated that ${\overline{F}}_0$ and ${\overline{\mathrm{P}}}_{\max }$ changed across h _PO conditions, while ${\overline{v}}_0$ remained constant. A lower h _PO led to a significantly higher ${\overline{F}}_0$ and ${\overline{\mathrm{P}}}_{\max }$ . These changes resulted in a steeper S _Fv leading to a more force-oriented profile, a lower optimal S _Fv and a greater F–v imbalance. Reducing h _PO and modifying F–v profile led, to some extent, to a reduction in h _max. Performance is a compromise between h _PO, ${\overline{\mathrm{P}}}_{\max }$ , and F–v imbalance, all influenced by countermovement depth. This explains why reducing countermovement depth to meet time constraint may lower performance.