Bellicha, A, Giroux, C, Ciangura, C, Menoux, D, Thoumie, P, Oppert, J-M, and Portero, P. Vertical jump on a force plate for assessing muscle strength and power in women with severe obesity: reliability, validity, and relations with body composition. J Strength Cond Res 36(1): 75-81, 2022-Muscle strength and power, particularly when assessed during multijoint movements such as vertical jump (VJ), are important predictors of health status and physical function. Vertical jump is mainly used in athletes, also in untrained or older adults, but has not yet been used in subjects with obesity. We aimed to assess the following in this population: (a) the reliability of VJ parameters, (b) their validity compared with isokinetic testing, and (c) their relations with body composition. In 20 women with severe obesity (mean [SD] age: 41.1 [11.6] years; body mass index: 43.9 [4.4] kg·m-2) without severe orthopedic disorders, VJ parameters, knee extension torque, and body composition were assessed using a force plate, an isokinetic dynamometer, and dual-energy x-ray absorptiometry, respectively. Excellent reliability was found for absolute peak power and peak force in VJ (intraclass correlation coefficient [95% confidence interval]: 0.95 [0.88-0.98] and 0.90 [0.77-0.96], respectively), and moderate to good validity of peak power and peak force compared with isokinetic torque (r = 0.79 and r = 0.67, respectively; all p < 0.01). Positive relations were found between peak force and peak power during VJ and lean body mass (r = 0.89 and r = 0.60, respectively; p < 0.01) and a negative relation was found between peak velocity or VJ height and fat mass (r = -0.65 and -0.64, respectively; p < 0.01). These results suggest that VJ on a force plate is a reliable and valid test for assessing muscle strength and power in severely obese subjects. Vertical jump testing is easy to implement, which can facilitate its use in both research and clinical testing in this setting (ClinicalTrials.govID: NCT03325764).
The debate about abortion is recurrently pervading not only politics and public health but also society at large, even within the utilization of mass media. The authors reinforce that access to reproductive health is a human rights issue and discuss facts and misconceptions associated with the procedure. They reframe the discussion and scripts sometimes found in pop culture, illuminating how attitudes towards reproductive rights may affect people. To address the polarization impasse, they propose using the lens of attachment relationships and offer corresponding solutions on three core levels: educational, social and narrative.
This study aimed at testing the possible correlation between rowers’ ability to generate power during a rowing Wingate test or a squat jump test and a rowing ergometer performance. Mean power developped during the Wingate test (PWIN), force, velocity and power output in squat jump (FSJ, VSJ and PSJ) and mean power (P1500) sustained during an all-out 1500-m sprint ergometer were measured in fourteen young rowers (15.3±0.6 yr, 178.5±8.8 cm, 67.9±10.8 kg). PWIN was significantly correlated to P1500 (r=0.90, P<0.001). FSJ, VSJ and PSJ were also significantly correlated to P1500 (r=0.54-0.87, P<0.001). Rowers presenting the highest power capacities, in either Wingate or squat jump test, were also the ones showing the best performances. In young rowers, the power capacity highlighted by Wingate and squat jump tests, are determinants for success in rowing performance.
Purpose This study aimed to investigate the coordination of lower limb muscles during a specific fencing gesture in relation to its mechanical effectiveness. Methods Maximal isokinetic concentric and isometric plantarflexor, dorsiflexor, knee and hip extensor and flexor torques of 10 female elite saber fencers were assessed and compared between both legs. Sabers completed three trials of a specific fencing gesture (i.e., marché-fente) on a 6.60-m-long force platform system. Surface EMG activities of 15 lower limb muscles were recorded in time with ground reaction forces and separated into four distinct assault phases. EMG signals were normalized to the muscle activity assessed during maximal isometric contraction. Mechanical and EMG data were compared between both legs over the entire assault and in each phase (ANOVA). Potential correlations between muscle strength and average EMG activities were tested (Bravais–Pearson coefficient). Results EMG activity patterns showed that rear hip and knee extensor and plantarflexor muscles were mainly activated during propulsive (concentric) phases, while front hip and knee extensor muscles were strongly solicited during the final braking (eccentric) phase to decelerate the body mass. Although fencers presented greater maximal hip (+10%) and knee (+26%) extensor strength in the front than in the rear leg (P < 0.05), rear hip and knee extensor strength was significantly correlated to the maximal anteroposterior velocity (r = 0.60–0.81). Moreover, muscle activity of the rear extensors was related to average velocity during the second propulsive phase (phase 3). Conclusions This study gathers the first evidence of a crucial role of the rear extensor muscles in fencing speed performance. Such findings suggest interesting perspectives in the definition of specific training or rehabilitation programs for elite fencers.
Correction to: Relationship between Force-Velocity Profiles and 1,500-m Ergometer Performance in Young RowersInt J Sports Med 2017; 38(13): 992-1000DOI: 10.1055/s-0043-117608
ObjectivesTo compare incidence rates of lower limb muscle injuries (LLMIs) and hamstring muscle injuries (HMIs) in 100 m, 200 m and 400 m sprints disciplines between finals, semi-finals and heats of international athletics championships.DesignProspective total population study.MethodsWe analysed in-competition LLMIs and HMIs of female and male athletes during eight championships between 2009 and 2022.ResultsLLMI and HMI incidence rates in 100 m finals were significantly higher than in heats and semi-finals for female and male athletes. HMI incidence rates were significantly higher in 200 m finals than heats and semi-finals for male athletes.ConclusionsLLMI and HMI risk was higher in finals compared to previous rounds during international athletics championships.
Wearable resistance (WR) training is a modality that allows athletes to perform loaded sport-specific movements to develop force and power outputs. The acute responses by which WR works is still relatively unknown, and the effects of WR load and location of the load has not yet been examined.To investigate the acute neuromuscular and stride characteristic responses to different wearable resistance (WR) loads and placements on the calf muscles during high-speed running.Ten well-trained subjects completed a workout of ten sets of three 10s runs at 18km.h-1 (20s of rest between runs and one min between sets). Five conditions were tested: (1) unloaded control, (2) bilateral 0.75 vs. 1.5% body mass (BM) loading on the distal posterior calf, (3) bilateral proximal vs. distal loading of 1.5% BM positioned posteriorly, (4) bilateral anterior vs. posterior loading of 1.5% BM positioned distally, (5) unilateral loading of 1.5% BM on the distal posterior calf. Data were collected using Electromyography (EMG) and back-mounted GPS-embedded accelerometers. Magnitude of differences of within athlete and between muscle comparisons were calculated using effect sizes (ES) ± 90% confidence limits (CL).No substantial differences in accelerometry data were observed between any of the loaded conditions and the control. EMG activity was lower for proximal loading compared to the control for the gluteus maximus (ES±90%CL; -0.72±0.41), vastus lateralis (-0.89±0.47) and vastus medialis (VM) (-0.97±0.46). Anterior loading induced substantially lower EMG activity for the semitendinosus (-0.70±0.48) and VM (-0.64±0.39) muscles compared with the control. EMG activity of the VM (-0.73±0.46) muscle was also substantially lower for posterior loading compared to the control. Unilateral loading induced no substantial differences in EMG activity between the loaded and unloaded legs.This preliminary study has provided a rationale for the performance of further investigations into the effects of WR lower limb loading on stride characteristics and EMG activity from a chronic standpoint using a larger population.
