Maleček, J, Malíř, R, Mašek, D, Matoušek, O, Ojanen, T, Oláh, V, Omcirk, D, Šimsa, J, Tufano, J, Vágner, M, and Třebický, V. From test to task: Relevance of basic physical fitness metrics in the context of military-specific performance. J Strength Cond Res XX(X): 000–000, 2026—Physical fitness assessments, such as push-ups, sit-ups, and 12-minute runs, remain central to military readiness evaluation; however, their capacity to explain variance in military-specific task performance remains insufficiently understood. This study investigated the relationship between these physical fitness assessments and performance in 6 simulated military-specific tasks. Twenty-nine physically active men (mean age = 22.6 years, SD = 3.0) completed the following fitness tests: maximal oxygen uptake (V̇ o ₂ max), body composition, aerobic endurance (12-minute run), anaerobic agility (shuttle run), muscular endurance (push-ups, sit-ups, pull-ups), explosive power (countermovement jump, seated medicine ball throw), grip strength, and maximal strength (1-repetition maximum hexagonal barbell deadlift). In addition, 6 military-specific tasks were performed in standardized 10.4-kg combat gear: 2 km loaded march, casualty drag, maximal single lift of a military pack, repeated lift and carry, modified fire and movement, and water can carry. Among the assessments, the only consistent field predictor was the 12-minute Cooper run, which related to both the 2 km loaded march ( β = −0.233, [–0.327 to −0.140]) and repeated lift and carry ( β = −0.062, [–0.089 to −0.034]). By contrast, strength and power measures were more task-specific: maximal single lift was associated with the seated medicine ball throw ( β = 0.112, [0.046 to 0.179]) and grip strength ( β = 0.685, [0.147 to 1.222]), while modified fire and movement time aligned with shuttle-run performance ( β = 0.963, [0.204 to 1.721]). These results suggest that military-specific tasks may provide a more valid criterion for occupational performance, with limited added predictive value of traditional tests beyond the Cooper run.

Background: Serve speed in tennis can be influenced by physical strength and toss kinematics, yet their interaction remains unclear in junior athletes. This study investigated the relationships between toss-related variables (zenith height, impact height, and zenith–impact differential), shoulder rotation strength, and serve speed in junior tennis players. Methods: Thirteen nationally ranked junior male players (mean age: 15.8 ± 0.9 years; body mass: 65.9 ± 5 kg; height: 181 ± 7 cm) participated. Isokinetic shoulder internal and external rotation strength (concentric/eccentric at 210°/s and 300°/s) were measured. High-speed 3D motion capture (Qualisys) recorded toss zenith, impact height and zenith–impact differential during flat serves directed into a designated 1 × 2 m target zone. Serve speed was measured by a radar gun. Correlation, mediation, and moderation analyses were conducted (n = 13; sensitivity ρ ≥ 0.69 for 80% power). Results: Impact height showed a significant positive correlation with successful (ρ = 0.746, p = 0.003) and unsuccessful serve speed (ρ = 0.776, p = 0.002). Moderation analyses showed that lower variability in impact height (p = 0.043) and in zenith–impact differential (p = 0.048) significantly strengthened the association between shoulder-rotator strength and serve speed. Conclusions: Moderation analyses revealed that lower variability in impact height and in the zenith–impact differential strengthened the relationship between shoulder strength and serve speed. Preliminary evidence suggests that consistent toss execution could enhance the translation of shoulder-rotation strength into serve speed in junior players.

Background/Objectives: Serve speed in tennis can be influenced by physical strength and toss kinematics, yet their interaction remains unclear in junior athletes. This study investigated how toss-related variables (zenith height, impact height, and zenith–impact differential) relate to shoulder rotation strength and serve speed in junior tennis players. Methods: Thirteen nationally ranked junior male players (mean age: 15.8 ± 0.9 years; body mass: 65.9 ± 5 kg; height: 181 ± 7 cm) participated. Isokinetic shoulder internal and external rotation strength (concentric/excentric) were measured at 210°/s and 300°/s. High-speed 3D motion capture (Qualisys) recorded toss zenith, impact height, and zenith–impact differential during flat serves directed into a designated 1 × 2 m target zone. Serve speed was assessed using radar gun. Correlation, mediation, and moderation analyses were conducted. Results: Impact height showed a significant positive correlation with successful (ρ = 0.746, p = 0.003) and unsuccessful serve speed (ρ = 0.776, p = 0.002). Moderation analyses showed that lower variability in impact height (p = 0.043) and in zenith–impact differential (p = 0.048) significantly strengthened the association between shoulder-rotator strength and serve speed. Conclusions: Moderation analyses revealed that lower variability in impact height and in the zenith–impact differential strengthened the relationship between shoulder strength and serve speed. These findings suggest that training should emphasize toss consistency to maximize the translation of shoulder rotation strength into serve speed.