Search Results (95)

Approximately two-thirds of athletes who are submitted to Anterior Cruciate Ligament Reconstruction (ACLR) never return to their preinjury level of performance, potentially due to muscle strength deficiencies or altered loading patterns during landing or jumping tasks. This study aimed to estimate individual muscle forces during a double-leg drop jump task, and assess sagittal plane between-limb asymmetries in muscle forces and ground reaction forces using a musculoskeletal modelling approach, in athletes who underwent ACLR. Thirty male field-sport athletes (age: 18–35 years; mass: 84.3 ± 12.3 kg; height: 180.2 ± 8.4 cm) post-ACLR (39.8 ± 3.9 weeks) using patellar or quadriceps tendon grafts were tested. Scaled musculoskeletal models were implemented in OpenSim, and muscle forces were estimated using the Computed Muscle Control optimization method. The contralateral limb exhibited greater vertical ground reaction forces across most of the rebound phase (d = 2.01). Compared with the contralateral limb, the ACLR limb showed reduced quadriceps (d = 1.72), soleus (d = 0.95), and gluteus maximus (d = 0.83) forces, indicating deficits in knee extensor, plantarflexor, and hip extensor neuromuscular function. Smaller asymmetries were found for the gluteus medius (d = 0.60) and hamstrings (d = 0.72), while other muscles showed symmetrical activation patterns. These results reveal persistent between-limb asymmetries in muscle recruitment and loading up to nine months post-ACLR, emphasizing the importance of targeted rehabilitation to restore symmetrical neuromuscular control during explosive movements. Full article

Jump height provides limited insight into movement strategies and muscle-tendon unit (MTU) contraction dynamics of the squat jump (SJ), countermovement jump (CMJ), and drop jump (DJ). This study investigated whether concentric phase variables differ significantly across these jumps. Twenty-three male athletes (age: 18.1 ± 0.7 years) from various sports performed the SJ, CMJ and DJ on a force plate. Variables included jump height (JH), concentric duration (ConT), concentric mean force (CMF), relative concentric mean force (rCMF), and concentric force index (CFI). Significant differences (p < 0.05) were observed in all variables across jump types. The CMJ led to the greatest JH (37.8 ± 4.1 cm) compared to SJ (34.6 ± 4.4 cm) and DJ (31.9 ± 5.0 cm). Conversely, the DJ produced the greatest rCMF (30.1 ± 2.7 N/kg) within the shortest ConT (125 ± 15 ms), compared to the SJ (16.2 ± 0.8 N/kg in 409 ± 48 ms) and CMJ (19.8 ± 1.0 N/kg in 273 ± 24 ms). Minimal shared variance and varied individual athlete rankings across jumps suggest that each jump elucidates different facets of MTU function. As a novel variable, the CFI showed poor correlation with JH (r = −0.103 to 0.002), suggesting it may provide insights beyond jump height alone. These findings support our hypothesis that SJ, CMJ, and DJ offer distinct diagnostic insights into varying MTU contraction dynamics and the physical components underpinning jump performance, indicating that longitudinal monitoring of the CFI and underlying components (rCMF/ConT) across these jumps could enhance athletic profiling. Full article

Background: Plyometric training (PT) and resistance training (RT) can improve jumping and sprinting performance, although their comparative effectiveness in elite female basketball players remain unknown. Objectives: To compare the effects of PT and RT on jumping and sprinting performance in elite female basketball players. Methods: Thirty elite female basketball players were randomly assigned to PT (n = 10), RT (n = 10) or control groups (n = 10, standard basketball training). Performance assessments before and after the interventions (8 weeks, 16 training sessions) included countermovement jump (CMJ) height and peak power, drop jump (DJ) height and reactive strength index (RSI), standing long jump distance (LJ), CMJ with arm swing (CMJA) height, running CMJA height, and 22.2 m linear sprint time. Performance changes were analyzed using linear and Bayesian mixed-effects models. Results: Compared to controls, RT and PT improved the RSI. Additionally, PT improved (p < 0.05; posterior probability >0: 99.4–99.9%) CMJ height, CMJ peak power, DJ height and RSI, LJ, CMJA, Running CMJA and sprint time when compared to both controls and RT. Conclusions: Compared to RT, PT induced greater jumping and sprinting performance improvements in elite female basketball players. Full article

Purpose: The primary aim of this study was to determine the efficacy of acute fish oil (FO) supplementation on indices of exercise-induced muscle damage (EIMD) in young healthy adults. Methods: Twenty-two healthy young male and females were randomly assigned to two experimental groups: fish oil (FO) or placebo control (CON). Participants performed a muscle damage protocol consisting of 10 sets of 10 plyometric drop jumps. Vertical jump height, isometric maximal voluntary contraction (MVC) torque, and systemic inflammation markers were assessed at pre-exercise, immediately post (post-0), post-24, post-48, and post-72 h. Results: Vertical jump performance and quadriceps peak torque significantly decreased in the CON group at post-0, 24, and 48 h (p < 0.05), while FO group recovered to baseline levels by post 48 h. Hamstring peak torque reductions recovered in the FO group at post-48 h but remained suppressed in the CON group until post-72 h (p < 0.05). Muscle soreness was significantly higher in the CON group compared to the FO group at post-48 h (p < 0.05). Systemic TNF-α levels significantly increased from baseline to post-0, 24, and 48 h in both groups (p < 0.05), with the CON group showing a trend toward incomplete recovery (p = 0.065). Conclusions: Our findings indicate that acute FO administration may modestly aid muscle recovery and reduce muscle soreness following EIMD in healthy young adults while the overall impact may be limited. Full article

Objectives: Plyometric training is a well-established method for enhancing jump performance in basketball and volleyball athletes but has certain limitations. Kettlebell training may provide a viable alternative as it mimics key biomechanical aspects of jumping, like explosive hip and knee extension during a ballistic hip–hinge pattern. Because evidence remains limited, this study aimed to compare the effects of both training methods. Methods: Thirty-eight volleyball and basketball club athletes (age: 22 (4.3); male = 29, female = 9) completed this study. Countermovement jump (CMJ), squat jump (SJ), drop jump (DJ), body fat percentage (FM), and muscle mass percentage (MM) were assessed pre- and post-intervention. The participants were assigned to one of three groups: a kettlebell training group (KbG), a plyometric training group (PG), or a control group (CG). Both the KbG and PG completed two supervised 25-min training sessions per week for six weeks, while the CG did not engage in any additional training intervention. The level of significance was set at p ≤ 0.05. Results: There were no significant differences in CMJ, SJ, and DJ performance between the groups before the intervention. Significant differences in change between the groups from pre- to post-test were found for the SJ (p = 0.006), but not for the DJ (p = 0.06), CMJ (p = 0.26), FM (p = 0.9), and MM (p = 0.55). Pairwise comparisons revealed significantly greater positive change in the KbG than in the CG for the SJ (p = 0.003) and DJ (p = 0.03). Within-group analyses showed significant improvements in the KbG for the CMJ (p = 0.04), SJ (p < 0.001), and DJ (p = 0.003) performance, whereas FM and MM did not change. Within the PG and CG, no significant change occurred. Conclusions: Kettlebell training effectively improved jump performance and may therefore serve as a valuable component within strength and conditioning programs for basketball and volleyball athletes. Full article

Background/Objectives: Understanding how muscle fatigue contributes to musculoskeletal injuries is critical in sports science. Although joint biomechanics during landing under fatigue has been studied before, limited research has focused on the layup phase under fatigue. This study examined the effects of fatigue on ankle, knee, and hip-joint biomechanics during layup and landing. We hypothesized that fatigue would increase peak vertical ground reaction force (GRF), peak knee extension angle, and peak joint moments. Methods: Fourteen healthy male participants performed 3-step layups and drop landings using their dominant leg on force plates. The fatigue protocol consisted of squat jumps, step-ups, and repeated countermovement jumps (CMJs), with fatigue defined as three consecutive CMJs below 80% of the participant’s pre-established maximum jump height. After a fatigue protocol, they repeated the tasks. Kinematic data were collected using an eight-camera Vicon system (100 Hz), and GRF data were recorded with two AMTI force plates (1000 Hz). Thirty-six reflective markers were placed on lower-limb anatomical landmarks, and data were processed using Visual 3D. Paired t-tests ($\alpha$ = 0.05) were conducted using SPSS (V26.0) to compare pre- and post-fatigue outcomes. Results: Significant increases were found in peak GRF during landing (pre: 3.41 $\pm$ 0.81 BW [Body Weight], post: 3.95 $\pm$ 1.05 BW, p = 0.036), and peak negative hip joint work during landing (pre: $-$0.34 $\pm$ 0.18 J/kg, post: $-$0.66 $\pm$ 0.43 J/kg, p = 0.025). Conclusions: These findings indicate that fatigue may alter landing mechanics, reflected in increased ground reaction forces and negative hip joint work. These preliminary findings should be interpreted cautiously, and future studies with larger samples and additional neuromuscular measures under sport-specific conditions are needed to improve ecological validity. Full article

Compression pants, as functional sportswear providing external pressure, are widely used to enhance athletic performance and accelerate recovery. However, systematic investigations into their effectiveness during anaerobic exercise and the impact of different pressure levels on performance and post-exercise recovery remain limited. This randomized crossover controlled trial recruited 20 healthy male university students to compare the effects of four garment conditions: non-compressive pants (NCP), moderate-pressure compression pants (MCP), high-pressure compression pants (HCP), and ultra-high-pressure compression pants (UHCP). Anaerobic performance was assessed through vertical jump, agility tests, and the Wingate anaerobic test, with indicators including time at peak power (TPP), peak power (PP), average power (AP), minimum power (MP), power drop (PD), and total energy produced (TEP). Post-exercise blood lactate concentrations and heart rate responses were also monitored. The results showed that both HCP and UHCP significantly improved vertical jump height (p < 0.01), while MCP outperformed all other conditions in agility performance (p < 0.05). In the Wingate test, MCP achieved a shorter TPP compared to NCP (p < 0.05), with significantly higher AP, lower PD, and greater TEP than all other groups (p < 0.05), whereas HCP showed an advantage only in PP over NCP (p < 0.05). Post-exercise, all compression pant groups recorded significantly higher peak blood lactate (Lamax) levels than NCP (p < 0.05), with MCP showing the fastest lactate clearance rate. Heart rate analysis revealed that HCP and UHCP induced higher maximum heart rates (HR_max) (p < 0.05), while MCP exhibited superior heart rate recovery at 3, 5, and 10 min post-exercise (p< 0.05). These findings suggest that compression pants with different pressure levels yield distinct effects on anaerobic performance and physiological recovery. Moderate-pressure compression pants demonstrated the most balanced and beneficial outcomes across multiple performance and recovery metrics, providing practical implications for the individualized design and application of compression garments in athletic training and rehabilitation. Full article

Background: Ischemic preconditioning (IPC) is a non-invasive, time-efficient strategy that has been shown to acutely enhance athletic performance. The present study examined the effects of 5 min of IPC on vertical and horizontal jump performance. A secondary aim was to explore the associations between outcomes of the 5-Hop (5-H) test and drop jump performance, in order to provide further evidence supporting the validity of the 5-H test for assessing reactive strength characteristics in trained jumpers. Methods: Twelve trained track and field jumpers (nine males, three females, age: 23.2 ± 2.9 years; height: 1.76 ± 0.07 m; body mass: 71.5 ± 8.0 kg) completed two conditions: an IPC condition applied to one leg and a control condition applied to the contralateral leg. In the first week, one leg was assigned to IPC and the other to the control condition, while in the second week, the conditions for each leg were reversed. Vertical single-leg performance was evaluated by drop jump (DJ) height, ground contact time, and reactive strength index (RSI). Horizontal jump performance was assessed by a five-hop (5-H) test during which total distance (TD), total time (TT), and reactive hopping index (RHI) were obtained. Results: Compared to the control condition, IPC enhanced DJ height (+ 3.6%) and RSI (+ 7.8%) (p < 0.05, g = 0.16 and 0.32, respectively) and reduced contact time (−4.4% p < 0.05, g = 0.41). Also, IPC resulted in significant improvements in TD (+ 4.1%) and RHI (+ 3.9%) during the 5-H test (p < 0.05, g = 0.32 and 0.42, respectively), while TT remained unchanged. Conclusions: A single cycle of IPC acutely improved vertical and horizontal jump performance and reactive strength indices in trained jumpers. These findings support the use of IPC as a practical, time-efficient method to enhance neuromuscular performance in explosive tasks. Full article

(1) Background: Dynamic knee valgus (DKV) is a common biomechanical risk factor for knee injuries, particularly in sports involving high-intensity movements, such as basketball. While neuromuscular control and structural alignment contribute to DKV, recent evidence indicates that lower limb muscle power (LLMP) and cardiorespiratory fitness (CRF) may significantly influence DKV. This study aims to examine the relationship among LLMP, CRF, and DKV in adolescent basketball athletes. (2) Methods: A total of 104 adolescent basketball athletes (63.5% boys), 12 to 17 years old (13.87 ± 1.46 years) participated in this study. Anthropometric and demographic characteristics such as sex, age, height, weight, and body mass index (BMI) were recorded. The Counter Movement Jump (CMJ) was used for the evaluation and prediction of the LLMP, the 20 m shuttle run test (20mSRT) was used for the evaluation and prediction of CRF, and the single-leg drop jump (SLDJ) was used for the evaluation of DKV via a two-dimensional (2D) kinematic analysis. Statistical analysis included Pearson and Spearman correlations, as well as multiple linear regression, to determine the relationship among LLMP, CRF, and DKV. (3) Results: A statistical analysis revealed strong correlations among LLMP, CRF, and DKV. Pearson’s correlation coefficients demonstrated significant associations between the VO₂max and frontal plane projection angle (FPPA) (r = 0.78, p < 0.001), as well as between LLMP and FPPA (r = 0.82, p < 0.001). Multiple linear regression analysis showed that VO₂max and LLMP together accounted for 85% of the variance in FPPA (R² = 0.85, p < 0.001). (4) Conclusions: The findings highlight that both aerobic capacity and lower limb muscle power significantly contribute to knee valgus control among adolescent basketball players. Implementing training programs focused on improving lower limb muscle power and cardiorespiratory fitness may enhance knee stability and reduce the risk of lower limb injuries. Given the strong predictive value of VO₂max and LLMP for knee control, targeted training programs focusing on neuromuscular conditioning and aerobic capacity may be effective for injury prevention. Full article

Coaches manipulate training variables to optimize and improve them, with intensity being crucial. Velocity-based training, measuring intensity by the movement speed, is advantageous over traditional methods. Flywheel training, offering concentric and eccentric loads, allows for supramaximal loading during the eccentric phase, enhancing muscle hypertrophy and performance and reducing injury risk. This study examines the specific effects of flywheel training on post-activation potentiation (PAP). Forty-one high-level male athletes performed flywheel half squats at fast (0.95–1.05 m/s), medium (0.65–0.75 m/s), and slow (0.35–0.45 m/s) speeds. Their drop jump performance was assessed at 30 s and 4, 8, and 12 min post-induction. Lower-limb kinematic data and ground reaction forces were recorded using infrared motion capture and force plates. Measures included peak collision force, peak extension force, knee joint extension moment, knee joint power, average power output, and vertical jump height. High-speed intensity significantly increased peak impact force, peak vertical ground reaction force, knee joint eccentric power, concentric power, and extension torque at 4, 8, and 12 min post-induction (p < 0.05). Fast- (0.95–1.05 m/s) and medium-speed (0.65–0.75 m/s) flywheel squats acutely improved lower-limb performance, especially vertical jump height, within 4–12 min post-stimulation. Fast-speed loading showed greater benefits for reactive strength and power output, while a medium speed also yielded meaningful gains. These findings support using movement velocity to guide flywheel training intensity. Full article

Background/Objectives: Human tendon properties influence athletic performance, and it was shown that Achilles tendon (AT) stiffness correlates with an athlete’s jumping performance across sports. However, the findings on this relationship between basketball and soccer are different. Hence, this study examined the relationship between AT stiffness and jumping performance in male athletes. Methods: Sixty-six males (24.9 ± 4.7 years; twenty-two basketball players (22.0 ± 4.1 years), and forty-four soccer players (26.3 ± 4.4 years)) participated. Reactive jumping performance (reactive strength index (RSI), jump height (JH), and ground contact time (GCT)) were assessed using drop jumps (fall height: 30 cm), and AT stiffness (supine position) was measured using the MyotonPro. Results: Soccer players had a significantly higher AT stiffness (826.8 ± 90.5 N/m) than basketball players (754.1 ± 80.1 N/m, p = 0.002), but no differences were found in JH, RSI, or GCT (p > 0.05). JH and AT stiffness significantly correlated in basketball players (r = 0.448) but not in soccer players (r < 0.100). The multiple linear regression indicated that AT stiffness is significantly influenced by the sport type (soccer or basketball), while age, mass, and height remained non-significant. Conclusions: Despite higher AT stiffness in soccer players (which can be explained by different activity regimens), a moderate correlation between jumping performance and AT stiffness was evident only in basketball. Given the versatile demands of both sports, tendon characteristics appear to have an influence on jumping performance. For future studies, investigating tendon characteristics represents a valuable addition to training and therapy scheduling. Full article

Background/Objectives: The aim of this study was to explore the differences in physical characteristics, leg strength, and jumping performance between 3 × 3 and 5 × 5 male basketball players. Methods: Twelve elite-level 5 × 5 basketball players (26.0 ± 13.0 years; 201.4 ± 6.6 cm; 95.50 ± 11.50 kg) and twelve elite-level 3 × 3 basketball players (26.7 ± 7.3 years; 193.0 ± 5.1 cm; 98.03 ± 9.77 kg), all male, were enrolled in the study. After anthropometric measurements and standardized warm ups, countermovement jump (CMJ), drop jump (DJ) and isokinetic strength testing were conducted, respectively. Results: An independent two-sample t-test revealed that 5 × 5 athletes were notably (p < 0.005) taller, with a lower body fat percentage (11.9 ± 3.6% vs. 18.6 ± 10.9%) and higher quadricep strength (317.21 ± 36.54 N·m vs. 284.76 ± 29.77 N·m and 313.32 ± 24.08 N·m vs. 285.87 ± 31.2 N·m for left and right leg, respectively). Conversely, 3 × 3 players displayed superior CMJ performance in concentric and eccentric peak forces, peak power, and reactive strength index. In the DJ, 3 × 3 players also excelled in eccentric peak force, reactive strength index, and jump height. Conclusions: The findings indicate that while 5 × 5 basketball players excel in body physique and in the strength of their lower body, 3 × 3 basketball players outperform them in power-related metrics. Full article

Muscle cramps often accompany a soldier’s high physical readiness in a tactical environment. Close monitoring of the muscles is required during the downward jump training at a certain height, which combines isometric, isotonic, and isokinetic movements. In this paper, we propose a preliminary study on vertical jumps and forward and backward body postures to detect the onset of cramps. Six soldiers were divided into two groups of three subjects each: group one, forward fall jumps, and the other group, backward fall jumps. A high-resolution camera captured the movements, which were then analyzed using Kinovea software version 0.9.5. Downward jumps with the body backward are less likely to cause cramps, and muscle bands are recommended to prevent leg muscle cramps. Full article

Background: Drop height has previously been used as an effective programming parameter in plyometric jump training. Less is known about the usage of maximal rebound jump height from a distinct drop height as a parameter for individualized plyometric jump training. Hence, the aim of this study was to contrast the effects of two different drop jump (DJ) training modalities using either the individualized maximal rebound height (MRHT) or a standard (SDHT) drop height on selected measures of physical fitness in young volleyball players. Methods: Thirty male young volleyball players aged 14 to 16 years were randomly assigned to an MRHT (n = 15) or an SDHT (n = 15) group. The MRHT group performed DJ exercises using a drop height according to the individual’s maximal rebound jump height from 30 cm, 40 cm, and 50 cm drop heights. The SDHT group performed DJs following a standardized drop height (30 cm) across the 8-week intervention period. The overall training volume was similar between MRHT and SDHT with one to three sets of 8 to 10 repetitions of DJ exercises per session. Before and after training, jump height and the reactive strength index (RSI) were taken as dependent variables from 30, 40, and 50 cm drop heights. In addition, dynamic balance (Y-balance test) as well as linear sprint and change-of-direction (CoD) speed were assessed. Results: Significant group × time interactions were found for jump height, balance, RSI, and linear sprint (p < 0.001; d = 0.12–3.42) but not CoD speed. Post hoc tests showed significant jump height improvements in favor of the MRHT group for drop heights from 30 cm (Δ20.4%, p < 0.001, d = 3.69), 40 cm (Δ20.3%, p < 0.001, d = 2.90), and 50 cm (Δ18.3%, p < 0.001, d = 3.37) and RSI50 (Δ30.14%, p < 0.001, d = 2.29). MRHT but not SDHT resulted in significant 5 m (Δ9.2%, p < 0.001, d = 1.32) and 20 m (Δ7.4%, p < 0.01, d = 2.30) linear sprint speed improvements. Conclusions: The findings demonstrate that MRHT but not SDHT improved DJ height, RSI, and linear sprint speed. Due to the importance of vertical jumps and short accelerations for overall competitive performance in volleyball, our results suggest that young male players should perform MRHT as part of plyometric jump training if the goal is to improve acceleration, reactive strength, and vertical jump performance. Full article

Exposure to the cold can negatively affect muscle performance. This study compared the effects of two different full-length, lower body, next-to-skin garments on thermal sensation, countermovement jump (CMJ) height and knee frontal plane angle upon landing following cold exposure against a control. After familiarisation, 13 male and 11 female recreationally active adults attended three separate laboratory testing sessions where a randomly assigned next-to-skin garment was used (compression, thermal and control (shorts)). A pre- and post-testing protocol comprising CMJ and drop landings interspersed with a sedentary cooling period of 40 min at 0 °C was adopted. High-speed motion analysis and subjective ratings of thermal sensation were recorded. Exposure to the cold significantly reduced thermal sensation (p < 0.001) scores and CMJ height (p < 0.001). Only female participants felt significantly warmer (p ≤ 0.009) in the next-to-skin garments. Losses in CMJ height were significantly reduced by the next-to-skin garments compared to the control with the thermal garment producing better results. There was little change in knee frontal plane angle upon landing in all the garments tested. Ambient cooling at 0 °C for 40 min had a significant effect on CMJ height and thermal sensation but not knee valgus upon landing. Participants in winter sports should consider next-to-skin garments in conjunction with proper warm-ups and re-warming techniques to protect themselves from the negative effects of the cold. Full article