Whether acute dry-land preconditioning improves jump height and swimming outcomes in breaststroke remains unclear. This original experimental study used a randomized crossover design to compare two whole-body vibration (WBV) protocols and a unilateral BOSU-based protocol with an active stable-ground half-squat Control condition in 14 competitive breaststroke swimmers. Sessions were separated by at least 72 h. Countermovement jump (CMJ) height, squat jump (SJ) height, 25 m breaststroke split time, and 50 m breaststroke final time were assessed before and after each condition. Linear mixed-effects models showed significant Condition × Time interactions for CMJ height and 25 m split time, but not for SJ height or 50 m final time. Planned interaction contrasts showed greater pre-to-post changes than Control for both WBV conditions in CMJ height and 25 m split time. WBV 4 mm produced the largest point estimates for both primary outcomes, although superiority was not established. BOSU estimates were favourable but non-significant. WBV therefore showed the most consistent evidence of favourable acute responses relative to an active half-squat Control, whereas unilateral BOSU remained promising but inconclusive. Swimming findings apply only to the fixed assessment sequence, and the 25 m split should be interpreted as a composite early-race indicator.

Background/Objectives: This systematic review examined whether oral vitamin D supplementation improves vitamin D status, health, and exercise outcomes in indoor-training aquatic athletes. Methods: We systematically reviewed randomized, placebo-controlled trials (>2 weeks) investigating vitamin D supplementation in competitive swimmers and divers. Six eligible trials (n = 246) were included and summarized descriptively. Results: Supplementation (2000–5000 IU/day for 12 weeks to 6 months) consistently increased serum 25(OH)D compared with placebo, with average increases up to 9.3 ng/mL. While higher doses occasionally improved muscle strength and lean mass, evidence showed no consistent benefits for swimming performance, immune function, or bone turnover. Additionally, higher body mass index (BMI) correlated with smaller 25(OH)D increases. Conclusions: Vitamin D effectively corrects deficiencies in aquatic athletes but lacks consistent ergogenic benefits. Therefore, in practice, supplementation should serve primarily as a targeted corrective measure for deficiency to support fundamental musculoskeletal health, rather than a generalized strategy for performance enhancement.

Efficient segmental pitch control is critical for butterfly swimming propulsion and alignment, yet its role in youth performance remains unclear. This study quantified head, shoulder, and hip pitch kinematics using wearable inertial measurement units (IMUs) in 41 competitive swimmers (9–11 years). Participants performed two maximal 25-m butterfly trials and were classified into faster and slower groups. Pitch angle, velocity, frequency, time, and pitch deviation index were extracted. Between-group differences were assessed using independent t-tests, and associations with performance were examined using Pearson correlations. Faster swimmers exhibited smaller head pitch angles during the Breath phase (p < 0.001, d = −2.01), along with greater shoulder pitch velocities and frequencies (all p < 0.05, d = 0.67–1.07). They also demonstrated shorter pitch times and lower pitch deviation indices (all p < 0.05, d = 0.66–1.92), indicating more efficient and stable movement patterns. In contrast, hip kinematics showed fewer and less consistent differences between groups. Several head and shoulder variables during the Breath phase were moderately correlated with sprint time (r = 0.32–0.43, p < 0.05). These findings suggest that sprint butterfly performance in youth swimmers is primarily associated with more controlled and stable upper-body pitch motion, particularly during breathing.

Age-related declines in physical capacity may partly reflect impaired mitochondrial bioenergetics and oxidative stress. This systematic review and meta-analysis evaluated the effects of oral coenzyme Q10 (CoQ10) supplementation on muscle health and physical capacity in adult populations with a study-level mean or median age ≥ 40 years. MEDLINE, Embase, Web of Science, Scopus, and CENTRAL were searched through July 2026 for randomized controlled trials lasting ≥2 weeks. Directly usable evidence formed primary random-effects models, whereas assumption-dependent estimates were included only in sensitivity analyses. Effect measures were expressed as mean differences (MDs) or Hedges’ g, as appropriate. Thirty-three trials involving 3317 randomized participants were included, and 21 contributed to meta-analysis. The relative VO₂peak/VO₂max estimate was small and imprecise (5 studies, n = 172; MD 0.73 mL·kg⁻¹·min⁻¹, 95% CI −0.07 to 1.54; I² = 0%; low certainty) and remained compatible with no benefit. Primary estimates were also uncertain for 6-min walking distances, handgrip strength, lower-limb strength, chair-rise performance, exercise duration, and muscle/lean-tissue quantity. Sensitivity analyses did not materially alter the overall interpretation. Evidence certainty was low or very low for all key outcomes. Current evidence does not establish clinically meaningful benefits of CoQ10 supplementation for aerobic capacity, muscle health, or physical function.