Aim: This study evaluated the effects of plyometric training with different set configurations on sprint speed, change of direction (COD), jump performance, and perceived exertion in youth football players. Method: Twenty-four U-19 players were randomized into three groups: Cluster Set (CLS, n = 8), Traditional Set (TRD, n = 8), and Control (CON, n = 8). CLS performed 8–10 sets of 2–3 repetitions, while TRD completed 2–3 sets of 8–10 repetitions in an 8-week plyometric program (2 sessions/week). The CON group did not train. Performance measures included 10 m, 20 m, and 30 m sprints, COD, Counter Movement Jump (CMJ), Reactive Strength Index (RSI), and Rate of Perceived Exertion (RPE). A repeated measures ANOVA analyzed group*time interactions. Results: Significant improvements were observed in CLS and TRD groups for sprints (10 m: f = 21.44; 20 m: f = 19.40; 30 m: f = 49.56; p < 0.001), COD (f = 14.66; p < 0.001), CMJ (f = 51.50; p < 0.001), and RSI (f = 24.91; p < 0.001). No changes occurred in CON (p > 0.05). Conclusions: CLS and TRD plyometric training improved sprint speed, COD, and jump performance, with CLS showing slightly superior results and better fatigue management.

The Effect of Respiratory Muscle Training on Aerobic and Anaerobic Strength in Adolescent Taekwondo Athletes

Background: This study aimed to determine the effect of the Nordic hamstring curl training (NHCT) program on athletic performance elements such as linear speed, change of direction (COD), jump performance (CMJ), and eccentric muscle strength (Nordic Hamstring Curl Breaking Point Angle—NHCBP) in young football players. Methods: The study group consisted of 40 male football players who were actively trained and had no previous eccentric training experience or reported any injuries. The participants were randomly divided into a training group (TG = 20) and a control group (CG = 20). The TG performed the NHCT program twice a week for eight weeks, in addition to their standard football training. The CG continued with standard football training. Results: The study findings revealed no statistically significant differences in the interaction between group and time in 10, 20, and 30 m sprint performance. However, statistically significant differences were found in CMJ performance in terms of group–time interaction (F = 19.99, p < 0.001, η² = 0.52), COD (F = 11.10, p < 0.004, η² = 0.38), and NHCBP (F = 6.14; p < 0.02; η² = 0.25). After the eight-week NHCT program, the experimental group showed improvements of 18% in CMJ performance, 8% in COD performance, and 25% in NHCBP performance. Conclusions: The NHCT program significantly increased hamstring muscle strength in football players, and this increase positively affected players’ linear speed and change of direction performance. NHCT has the potential to enhance athletic performance in football.

Background: Tennis requires movement abilities in changing playing situations. This article investigates the relationship between lower extremity strength asymmetry ratio and linear and multidimensional running performances in female tennis players. Methods: A total of 56 female tennis players, with a mean age of 15.44 ± 0.50 years, participated in the study—the research design involved three sessions at 48-hour intervals. In the first session, athletes performed dominant and non-dominant countermovement jump (CMJ) and board jump (BJ) tests. The second (sec) session included 10-meter (−m) and 30-m linear running performance tests, while the final session assessed multidimensional running performance with a change of direction (COD) test. The relationship between CMJ and BJ asymmetry ratios and linear and multidimensional running performances was analysed using the Pearson correlation coefficient. Bilateral asymmetry rates in linear and multidimensional running performance were determined through linear regression analysis. Results: The dominant CMJ recorded 17.56 ± 3.47 cm, while BJ was 130.23 ± 21.76 cm, and the non-dominant CMJ measured 16.79 ± 4.51 cm with a BJ of 147.52 ± 30.97 cm. The athletes had a CMJ asymmetry rate of 12.67 ± 11.29% and a BJ asymmetry rate of 7.19 ± 5.28%. A relationship was seen between the CMJ asymmetry rate and 30-m running performance (r = 0.368, p < 0.05). There was no correlation between BJ asymmetry rate and 10-m running performance. Significant correlations were found between 30-m (r = 0.364) and COD (r = 0.529) running performances (p < 0.05). Conclusions: It can be said that the CMJ asymmetry ratio may negatively affect 30-m and the BJ asymmetry ratio may negatively affect 30-m and COD performance.

This study examined the effects of different inspiratory muscle training (IMT) on lactate concentration and utilization during high-intensity exercises. Participants were divided into the following three groups: a chronic inspiratory training group (CRG), an acute inspiratory training group (ARG), and a control group (CG). Participants in the CRG accomplished IMT at an exercise intensity of 60–90% of the maximum inspiratory pressure (MIP) with 30 breaths twice a day for 8 weeks, and those in the ARG performed IMT at an intensity of 40–50% of the MIP for approximately 20 min in the pre-training warm-up phase three times a week. Body composition tests, maximum oxygen uptake, anaerobic power tests, and lactate concentrations of participants were evaluated before and after the intervention. Three consecutive anaerobic power tests (Wingate) were performed to observe changes in lactate concentration and utilization during high-intensity exercises. Blood lactate concentrations were measured immediately at the end of each anaerobic power test, after a 75-s rest, and during passive rest at the 2nd, 3rd, 4th, 5th, 10th, and 15th min of recovery. The results of the analysis of variance (ANOVA) revealed a significant decrease in blood lactate concentration only in the CRG immediately after the first Wingate test, whereas significant differences in the ARG and the CG were observed after the third Wingate test. After the last Wingate test, a significant decrease was observed after 5 min of recovery in the CRG and after 10 and 15 min of passive rest in both training groups. Herein, we conclude that IMT decreases blood lactate concentration after intense exercise and accelerates lactate utilization during recovery.