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Climate change and invasive species are two major drivers of biodiversity loss and their interaction may lead to unprecedented further loss. Invasive ectotherms can be expected to tolerate temperature variation because of a broad thermal tolerance and may even benefit from warmer temperatures in their new ranges that better match their thermal preference. Multi-trait studies provide a valuable approach to elucidate the influence of temperature on the invasion process and offer insights into how climatic factors may facilitate or hinder the spread of invasive ectotherms. We here used marsh frogs, Pelophylax ridibundus, a species that is invading large areas of Western Europe but whose invasive potential has been underestimated. We measured the maximal and minimal temperatures to sustain physical activity, the preferred temperature, and the thermal dependence of their stamina and jumping performance in relation to the environmental temperatures observed in their invasive range. Our results showed that marsh frogs can withstand body temperatures that cover 100% of the annual temperature variation in the pond they live in and 77% of the observed current annual air temperature variation. Their preferred body temperature and performance optima were higher than the average temperature in their pond and the average air temperature experienced under the shade. These data suggest that invasive marsh frogs may benefit from a warmer climate. Broad thermal tolerances, combined with high thermal preferences and traits maximised at high temperatures, may allow this species to expand their activity period and colonise underexploited shaded habitat, thereby promoting their invasion success.

Background Ageing is associated with sarcopenia, osteoporosis, and increased fall risk, all of which contribute to increased fracture risk. Mechanically, bone strength adapts in response to forces created by muscle contractions. Adaptations can be through changes in bone size, geometry, and bending strength. Muscle mass is often used as a surrogate for muscle force; however, force can be increased without changes in muscle mass. Increased fall risk with ageing has been associated with a decline in muscle power—which is a measure of mobility. The aims of this study were as follows: (i) to investigate the relationship between muscle parameters in the upper and lower limbs with age in UK men and the influence of ethnicity on these relationships; (ii) to examine the relationships between jump force/grip strength/cross‐sectional muscle area (CSMA) with bone outcomes at the radius and tibia. Methods White European, Black Afro‐Caribbean, and South Asian men aged 40–79 years were recruited from Manchester, UK. Cortical bone mineral content, cross‐sectional area, cortical area, cross‐sectional moment of inertia, and CSMA were measured at the diaphysis of the radius and tibia using peripheral quantitative computed tomography. Lower limb jump force and power were measured from a single two‐legged jump performed on a ground‐reaction force platform. Grip strength was measured using a dynamometer. Associations between muscle and bone outcomes was determined using linear regression with adjustments for age, height, weight, and ethnicity. Results Three hundred and one men were recruited. Jump force was negatively associated with age; for every 10 year increase in age, there was a 4% reduction in jump force (P < 0.0001). There was a significant age–ethnicity interaction for jump power (P = 0.039); after adjustments, this was attenuated (P = 0.088). For every 10 year increase in age, grip strength decreased by 11%. Jump force was positively associated with tibial bone outcomes: a 1 standard deviation greater jump force was associated with significantly higher cortical bone mineral content 3.1%, cross‐sectional area 4.2%, cortical area 3.4%, and cross‐sectional moment of inertia 6.8% (all P < 0.001). Cross‐sectional muscle area of the lower leg was not associated with tibial bone outcomes. Both grip strength and CSMA of the arm were positively associated, to a similar extent, with radius diaphyseal bone outcomes. Conclusions Jump force and power are negatively associated with age in UK men. In the lower limb, the measurement of jump force is more strongly related to bone outcomes than CSMA. It is important to consider jump force and power when understanding the aetiology of bone loss and mobility in ageing men.

Study aim: The aim of the study was to examine biomechanical characteristics of taekwondo athletes comparing kicks and punches with laboratory tests of muscle strength and power. Material and methods: Six male taekwondo athletes participated in this study. Measurements of maximal punching with the rear hand (hook and straight punches) and kicking (Apdolio and Dwit Chagi) force were performed on a boxing dynamometer. Also, the following laboratory tests were performed: jump height and power output in counter movement jump (CMJ) and spike jump (SPJ), muscle strength for 10 muscle groups and force-velocity (F-v) relationship. Results: Mean maximal straight and hook punching forces were 1659.2 ± 254.2 N and 1843.8 ± 453.3 N, respectively. Maxi­mal Apdolio rear leg, Apdolio lead leg and Dwit Chagi rear leg kicking forces were 3541.3 ± 1130.3 N, 3205.3 ± 965.1 N and 3568.0 ± 1306.0 N, respectively. The heights of jumps were 0.501 ± 0.040 m (CMJ) and 0.554 ± 0.034 m (SPJ). A strong cor­relation between the maximal force of a punch and maximal joint torques was observed. Conclusions: The values of kicking forces developed in a simulated fight were lower than the forces developed in the test of individual kicks. Strong relationships were observed between leg power developed in the SPJ and force of individual Apdolio kicks performed with the lead (r = 0.87, p < 0.05) and rear leg (r = 0.74). Based on these findings, it was concluded that maxi­mal joint torques and height of the SPJ could be used as a proxy of kicking force.

Background/Aims: To characterize the relationship between muscle function and auxology in preterm born children. Methods: Forty-five preterm born children (birth weight ≤1,500 g with mean ± SD: 1,069 ± 281 g; median of gestational age: 29 weeks; 50% multiple births) were analyzed for auxological parameters (weight, height) and muscle function at the age of 7 years. Maximal isometric grip force (MIGF) and ground reaction forces of goal-directed counter-movement jumping were measured using the Preston dynamometer and the Leonardo force plate. MIGF, peak jump force (PJF), peak jump power (PJP) and the maximal velocity of take-off (V max ) were analyzed for their relationship to perinatal risk factors and actual auxological parameters. Results: With reference to age, weight-standard deviation score (SDS) and height-SDS were lower than in the reference population. With reference to height, MIGF-SDS and PJP-SDS were lower than in reference individuals. Children with intraventricular hemorrhage (IVH) had lower PJP-SDS and V max than children without IVH. PJP-SDS was lower than PJF-SDS in children with IVH. Conclusion: Analyses showed a discrepancy between maximal force and power due to a decline of V max in children with IVH.

The present study comprised 29 adolescents and young adults (15 females, 14 males; aged 14.1–23.9 years) with congenital heart disease (CHD) and focused on the interaction between the biomechanical system and CHD. Individuals were characterized by auxological (height, weight), dynamometric (MIGF, maximal isometric grip force) and mechanograpic parameters (V max , maximal velocity; PJF, peak jump force; PJP, peak jump power; time of five stand-ups in chair-rising test). PJF, PJP and MIGF were transformed into height-related SD-scores. MIGF-SDS and PJP-SDS were lower in the CHD patients than in reference individuals. PJP-SDS was lower than PJF-SDS. PJP-SDS was correlated to V max ( r  = 0.62) and to the time of five-stand-ups in chair-rising ( r  = −0.62). Transcutaneous oxygen saturation and NYHA classes were correlated to V max ( r  = 0.42 and r  = −0.57, respectively) and to chair-rising performance ( r  = −0.60 and r  = 0.50, respectively). To conclude, individuals with CHD are characterized by an impaired inter- and intramuscular coordination, which is characterized by a greater decrease in muscular power than muscle force.

Countermovement bipodal jumps (CMJs), are widely used for health and performance assessment, but the software required for such analyses is often costly. The study aim was to examine the validity of an Excel/VBA spreadsheet for comprehensive CMJ kinetic analysis. The outcomes have been informed from scientific literature, and the spreadsheet includes modules for data filtering and photogrammetric analysis. To evaluate its validity, 21 participants performed CMJs on a dual force platform system, and the primary outcomes were compared with those derived from prestigious software (MARS 4.0). When jump height was calculated based on take-off speed and flight time the Mean Absolute Errors were 1.79 and 0.69 cm and the minimal detectable changes (MCD) were 1.28 and 0.16 cm. For the propulsive impulse, the error was 5.5 N · s and the MCD was 5.41 N · s. The intraclass correlations were 0.932 (0.902–0.953), 0.984 (0.977–0.989), and 0.940 (0.914–0.959), respectively, demonstrating a strong relationship, and residuals exhibited homoscedasticity. Considering the variability reported in previous studies for intra- and inter-subject comparisons, these errors are minimal, highlighting the spreadsheet’s sensitivity. With its exhaustive analytical capabilities and customizable features, this template serves as a valuable tool for trainers, physiotherapists, and academic teaching settings.

Force-velocity characteristics in multi-joint movements, specifically vertical jump, have been relatively unexplored in the literature. There were five main goals in this study: (1) define the force-velocity relationships for a multi-joint movement and compare them to Hill's force-velocity curve, (2) compare several types of force-velocity curves in a multi-joint movement, (3) define the power-load and power-velocity relationships in a multi-joint movement for the obtainable ranges of force and velocity, (4) since the entire theoretical power-velocity curve was not obtainable because of physical limitations, determine whether this experiment lies in the ascending or descending portion of the theoretical curve, and (5) determine the load and velocity at the instant of maximum power production. Ten well-trained subjects performed maximum effort, noncountermovement vertical jumps with a range (80% bodyweight unloading–125% bodyweight loading) of external loads. Each subject performed 28–34 trials at 14–17 conditions. The instant of maximum velocity was used as the time to measure all other variables. Jumps with the highest COM velocity at each condition were analyzed. Relationships were identified as ‘Hill-like’ if they were descending, had upward concavity, and 0 < α/Fo < 1. All variables studied in this investigation (maximum velocity of the center of mass (VCM), maximum knee angular velocity (Vk), maximum leg extension velocity (VLE), ground reaction force (GRF), and knee moment) were plotted against load. None of these relationships were Hill-like. Various variable combinations were compared to each other and to Hill's curve. Only GRF vs. VCM (video), vs. Vk, and VS. VLE were Hill-like. The best fit was GRF vs. VCM (video), fit with Hill's curve. Power, calculated by multiplying GRF and VCM, varied as expected with VCM and was on the descending part of the theoretical power-velocity curve. Maximum power corresponded to 37–61% of the maximum squat lift of the subjects and ∼56% of maximum velocity. This study successfully determined the force-velocity and power-velocity relationships for a multi-joint movement. Theoretical reasons why there was limited agreement with Hill's curve were discussed. No other study known by the author covers as wide a range of forces and velocities in vertical jumping.

This study investigated whether toe flexor strength and foot arch height were related to force components during the ground contact phase in vertical jump performance. The toe flexor strength, foot arch height and vertical jump performance were studied in 31 healthy young men. For the measurement of toe flexor strength, participants explosively exerted maximum force on a toe grip dynamometer. The maximum isometric force (Fmax) and the rate of force development (RFD) of the toe flexor strength were evaluated. Foot arch height was assessed as the distance between the navicular tuberosity and the floor. Fmax and foot arch height were normalized by body mass (rFmax) and height, respectively. Three types of vertical jumps without arm swing were performed on a force plate: a squat jump (SJ), a countermovement jump (CMJ), and a rebound jump (RJ). Fmax, rFmax and RFD of the toe flexor strength were positively correlated with the vertical jump height in the SJ (r = 0.408, r = 0.452, r = 0.514) and CMJ (r = 0.377, r = 0.444, r = 0.548) and the rebound jump index in the RJ (r = 0.549, r = 0.582, r = 0.575); however, foot arch height was not correlated with the vertical jump performance, and it was only significantly correlated with the minimum ground reaction force relative to body weight during the unloading phase of the CMJ (r = -0.366). These results suggest that the toe flexor strength is an important parametre for enhancing the jump performance.

A necessarily high standard for physical readiness in tactical environments is often accompanied by high incidences of injury due to overaccumulations of neuromuscular fatigue (NMF). To account for instances of overtraining stimulated by NMF, close monitoring of neuromuscular performance is warranted. Previously validated tests, such as the countermovement jump, are useful means for monitoring performance adaptations, resiliency to fatigue, and risk for injury. Performing such tests on force plates provides an understanding of the movement strategy used to obtain the resulting outcome (e.g., jump height). Further, force plates afford numerous objective tests that are valid and reliable for monitoring upper and lower extremity muscular strength and power (thus sensitive to NMF) with less fatiguing and safer methods than traditional one-repetition maximum assessments. Force plates provide numerous software and testing application options that can be applied to military’s training but, to be effective, requires the practitioners to have sufficient knowledge of their functions. Therefore, this review aims to explain the functions of force plate testing as well as current best practices for utilizing force plates in military settings and disseminate protocols for valid and reliable testing to collect key variables that translate to physical performance capacities.

The aim of the current study was to compare the reliability and validity of jump variables determined from torso- and waist-worn inertial measurement units (IMU) in comparison to force platform measures. Twenty-seven students-athletes completed eight countermovement (CMJ) and squat jumps (SJ) on a force platform with IMUs mounted on the pelvis and torso. Variables including jump height and phase-specific duration, impulse and power were calculated from force platform and both IMUs independently. Considering both IMU locations, the coefficients of variation (CV) observed for all CMJ variables were ≤ 2.5 % larger than the force platform with the exception of concentric impulse with the torso-worn worn IMU (6.9 %). Differences in CVs observed between IMU and force platform variables appeared greater in the SJ. For velocity-derived jump height and concentric impulse from both IMU placements, and torso-worn IMU mean power, CVs were > 2.5 % larger than the force platform. Both IMU placements overestimated jump height determined by flight time (+22 to +35 %) and underestimated jump height determined by take-off velocity (−10 to −18 %). In conclusion, the reliability of IMU metrics was largely comparable to the force platform. However, systematic bias was observed for most metrics. Practitioners should exercise caution if seeking to model jump performance with IMUs.