Objectives: The aim of this study was to assess the relationship between the countermovement jump (CMJ) and sprint performance of professional football players, and to determine which strength and speed elements assessed by the CMJ translate into effective running. Methods: The research sample comprised 87 male professional football players (age 23.7 ± 4.20 years; body mass 82.33 ± 6.56 kg; body height 1.86 ± 0.05 m) who performed the CMJ on a dual-force platform, as well as the 30 m sprint test. The time and velocity of the run were recorded by photocells at 0, 5, 10, and 30 m of the distance. Results: No significant differences were noted in the time or velocity of the sprint over the initial 5 m between the groups of football players with a higher and lower braking rate of force development (RFD) in the CMJ (p > 0.05). However, at subsequent intervals (5–10 m and 10–30 m), players with a higher braking RFD achieved significantly better time and velocity than those with a lower RFD. Significant correlations in the group with a lower braking RFD between the CMJ and sprint variables occurred in the propulsion phase of the CMJ and most of them were in the first interval (0–5 m). In the group with a higher braking RFD, significant relationships were visible in both the propulsion (concentric) and braking (eccentric) phases of the CMJ, mainly during the second and third intervals of the sprint test. Conclusions: The noted observations may suggest that the relationship between strength and running performance is more complex than previously indicated, and that higher strength in the CMJ does not fully correlate with better sprinting. Therefore, it has been hypothesized that training aimed at generally increasing strength may not always be fully beneficial for running performance in football players and hence specific training guidelines are suggested for targeted strengthening of the required muscle performance characteristics. This may possibly contribute to reducing the unnecessary muscle overload during both training and matches, thereby preventing sports-related injuries.

Background/Objectives. Despite growing interest in capacitive-resistive electric transfer TECAR) and Vibration therapy (VT), their comparative effectiveness in sports recovery remains unclear. This study aimed to evaluate and contrast the short-term effects of TECAR and VT on neuromuscular recovery following eccentric muscle fatigue, relative to passive rest, in active young adults. We hypothesized that both interventions would accelerate recovery and potentially reduce injury risk. Methods. Forty-one participants were randomized into two groups: TECAR therapy (Group 1) and VT (Group 2). Neuromuscular function was assessed at baseline, post-exercise, and post-intervention using tensiomyography (TMG) and electromyography (EMG). Results. Both groups showed a significant increase in EMG MDF intercept after exercise. Post-intervention, VT induced a further rise in this parameter, whereas TECAR stabilized values without significant change. In the contralateral resting limb, increases persisted after exercise and passive recovery. Between-limb differences were significant only in the TECAR group. TMG analysis revealed a non-significant but large-effect increase in contraction delay (Td) post-exercise, followed by significant reductions after both interventions. In the left limb, Td changes were not significant. For maximal displacement (Dm), both VMO and VLO muscles demonstrated a significant decrease post-exercise and a marked recovery after both therapies. Other TMG parameters (Ts, Tc, Tr) showed no significant changes. Conclusions. Both TECAR and VT effectively enhanced neuromuscular recovery after eccentric exercise. TECAR demonstrated a modest but consistent advantage, particularly in normalizing muscle recruitment and restoring mechanical properties, making it suitable in contexts requiring rapid recovery. VT, however, remains a more accessible and cost-effective modality. These findings support the application of both techniques in sports recovery, while highlighting the need for further research in professional athletes and diverse exercise settings to optimize regeneration strategies and reduce injury risk.

In recent years, many studies on the safe return to sport (RTS) have been published, but there are still no clear and validated guidelines. After ACL reconstruction between limbs, asymmetry of muscle strength affects knee mechanics during walking and running, and asymmetrical joint kinematics and kinetics are considered as a strong risk factor of musculoskeletal injury. Therefore, proper diagnosis of any motor deficits remaining after ACL reconstruction seems particularly important. The aim of this study was to analyze how many tests should be included in the RTS test battery and which of them are most indicative for functional deficits related to anterior cruciate ligament (ACL) reconstruction. Sixty-five male football players (age 18–25 years) were divided into three groups: ACL group—after ACL rupture and reconstruction, mild injury group—post mild lower limb injuries, and the control group—without injuries. They performed five tests: Functional Movement Screen, Tuck Jump Assessment, Y-balance Test, Hop Test for Distance, and Isokinetic Test. The Composite Score of Readiness (CSR) index was calculated and expressed as the sum of z-scores. The multiple regression model for all tests was calculated, and then redundant variables were excluded. We observed that all tests significantly influenced the final CSR index. The Y-balance Test, Tuck Jump Assessment, and Isokinetic Test for knee flexion influenced the final CSR index the most, which means that these tests are greatly indicative of functional deficits related to ACL reconstruction. The strength of the extensor (quadriceps) muscle and the quadriceps/hamstring ratio appeared to be non-sensitive for testing functional deficits related to ACL reconstruction. If the test battery includes 4–5 tests, it better differentiates the athletes following ACL reconstruction from those after mild injuries, even if they all were cleared to play.

Objectives: Rupture of the anterior cruciate ligament (ACL) is a severe injury common in sports. It also has a high rate of re-injury. The aim of this work was to assess hamstring muscle fatigue in active football players after ACL reconstruction who were cleared to play and to determine symmetry between the lateral and medial hamstring muscles. Methods: In professional football players post ACL reconstruction (n = 25) and non-injured players (n = 26), the bioelectrical activity of the medial (biceps femoris—BF) and lateral (semimembranosus and semitendinosus—SEM) hamstring muscles was measured during 60 s of isometric contraction. The fatigue variables were calculated using the Continuous Wavelet Transform (CWT) tool. Results: The football players following ACL reconstruction demonstrated significant asymmetry in fatigue of the lateral and medial hamstring muscles, with greater fatigue in the SEM compared to the BF muscle. Moreover, in those after reconstruction, the changes are more pronounced, with higher muscle fatigue in both limbs (they have lower MDF than non-injured players) and more severe SEM muscle insufficiency (noted in both limbs but with greater intensity in the non-operated one). Conclusions: The higher SEM muscle fatigue observed in this study influenced the lateral-to-medial activation ratio within the hamstring muscle, which may be a probable cause of this muscle’s insufficiency in laterally stabilizing the knee in the frontal and transverse plane. Furthermore, the hamstring muscles after reconstruction were more fatigued in both limbs, which may be another risk factor for ACL graft rupture. Therefore, increased fatigue in specific hamstring muscles may indicate the direction in which knee stabilization is compromised due to ACL overload. A muscle that becomes fatigued and inefficient more quickly also becomes ineffective in performing its function sooner, which can lead to increased overloading forces acting on the ACL graft.

Background/Objectives: Isokinetic testing is widely used after anterior cruciate ligament reconstruction (ACLR), but isolated knee strength may not reflect function during braking, re-acceleration, and stabilization. This study examined relationships between isokinetic strength and vertical and multidirectional performance in professional football players after ACLR and compared asymmetry across functional domains. Methods: Eleven male professional players, 12–40 months post-ACLR and back in unrestricted training and competition, completed isokinetic concentric knee extensor and flexor strength testing, single-leg countermovement and drop jumps, and unilateral and bilateral forward and lateral jumps on 3D force-plates. Limb differences, strength–performance associations, bilateral contributions, and domain-specific asymmetry were assessed. Results: No operated–non-operated limb difference remained significant after Holm correction. Knee extensor strength was positively associated with drop-jump reactive strength index (ρ = 0.612), countermovement-jump height (ρ = 0.491), anterior–posterior braking impulse during forward hop-in (ρ = 0.382), and propulsive impulse during forward hop-out (ρ = 0.442); however, none of the eight prespecified strength–performance correlations was statistically significant either before or after Holm adjustment. Median asymmetry differed across domains, reaching 20.9% for temporal control and stabilization and 14.7% for directional braking, compared with 9.9% for strength and 6.2% for vertical performance. Fifty percent of players had a median multidirectional-task asymmetry ≥20%. The operated limb contributed 49.9–53.0% of the total output during bilateral tasks. Conclusions: The absence of significant group-level differences in isokinetic strength and vertical jump outcomes did not exclude asymmetries in directional braking and stabilization. Isokinetic, vertical, and multidirectional assessments provide complementary, non-interchangeable information after ACLR. Multidirectional testing may therefore provide additional information on movement strategies that is not captured by strength and vertical jump tests alone.

Background: Although Capacitive–Resistive Electric Transfer (TECAR) and vibration therapy (VT) are increasingly used in sports recovery, their effects on muscle oxygenation remain unclear. Objectives: This study compared the short-term influence of TECAR and VT on muscle oxygenation following eccentric exercise in young, active adults. We hypothesized that both interventions would support early metabolic recovery, as reflected by changes in muscle oxygenation, and potentially reduce the risk of musculoskeletal overuse. Methods: Forty-one young, recreationally active adults (age: 19 ± 2 years; height: 168 ± 9 cm; body mass: 63 ± 13 kg) were randomized into two groups: TECAR therapy and VT. Muscle oxygenation was assessed at baseline, post-exercise, and post-intervention using the arterial occlusion method with a MOXY muscle oxygenation monitor (Fortiori Design LLC, USA). The primary variables were mVO₂ (muscle oxygen consumption), ΔSmO₂ (change in oxygen saturation during occlusion), and ΔtHb (change in hemoglobin level during occlusion). Data were analyzed using a two-way repeated-measures ANOVA with post hoc Tukey tests, and statistical significance was set at p < 0.05. Results: Eccentric exercise significantly reduced mVO₂ in both groups (VT: −0.18 ± 0.40 to −1.62 ± 0.70; TECAR: −0.12 ± 0.40 to −1.24 ± 0.70), indicating decreased metabolic demand. Following recovery, mVO₂ increased in both groups (VT: −0.86 ± 0.50; TECAR: −0.35 ± 0.40), with no significant between-group differences (p > 0.05). ΔSmO₂ also decreased after exercise (VT: −0.7 ± 0.4 to −3.2 ± 0.9; TECAR: −0.9 ± 0.6 to −3.45 ± 0.7). After recovery, ΔSmO₂ partially returned to baseline (VT: −2.6 ± 0.8; TECAR: −1.35 ± 0.4), with no significant between-group differences. ΔtHb increased following exercise in both groups (VT: 0.03 ± 0.04 to 0.13 ± 0.09; TECAR: 0.03 ± 0.04 to 0.15 ± 0.07) and decreased after recovery to similar levels (VT: −0.05 ± 0.05; TECAR: −0.06 ± 0.04; p > 0.05). Conclusions: Both TECAR and VT were associated with improved muscle oxygenation during early recovery after eccentric exercise, as reflected by increases in mVO₂ and comparable ΔtHb responses. Although ΔSmO₂ tended to decrease more after VT, this difference was not statistically significant and should be interpreted cautiously. Overall, both modalities appear to be effective recovery-supporting strategies, while further controlled studies are needed to clarify their role in different athletic populations and exercise contexts.