The Effect of the Annual Training Cycle on Aerobic Capacity in Division I Female Soccer Players

Purpose: To assess the effect of variable training stress throughout the annual training cycle on aerobic capacity (AC) in female soccer players. Methods: Eleven Division l female soccer players (Mean ± SD: 19.3 ± 1.0 yrs; 164 ± 6.4 cm; 60.1 ± 5.4 kg; 19.44 ± 3.5 %BF, 48.3 ± 4.0 kg FFM, 43.3 ± 3.3 ml/kg/min VO2max) were tested across the annual training cycle at six specific time points (B1-B6): post-season 2016 (B1), transition (detraining) (B2), spring-season (B3), pre-season (B4), mid-season (B5), and post-season 2017 (B6). Prior to exercise for each testing block, subjects arrived at the lab where height, weight, and body density (3-site skinfold method) were measured. Body fat was then estimated by using the Brozek equation. After a 5min self-selected warmup on the treadmill, subjects completed an incremental treadmill test to measure VO2max. VO2 values were collected each minute of the tests by using a 15sec average to assess AC. A 2x6 repeated measures ANOVA was used to analyze AC and fat free mass (FFM) changes across te annual training calendar (B1-B6). The LSD post hoc analysis was used if significant differences were found. RESULTS: Statistical analysis revealed a significant main effect of time on AC and FFM (F1,5 2513.1, p = 0.001), with an observed power of 1.0. Pairwise comparisons showed a significant increase (Δ +16.3%, p \u3c 0.01) in AC along with increased FFM (Δ +2.4%, p = 0.027) between B1-B3 following the 2016 competitive season (B1). However, AC decreased (Δ -7.0%, p = 0.021) without a significant change in FFM from B3 prior to the competitive season (B4). Aerobic capacity and FFM remained unchanged across the 2017 competitive season (B4-B6) despite the reduced AC from B3. CONCLUSION: Following the 2016 competitive season (B1), AC increased (p \u3c 0.05) indicating the reduced training load over the transition period (B2) increased AC without a change in FFM. Aerobic capacity and FFM increased significantly after the spring season training (B2-B3) where concurrent style training was largely incorporated. Aerobic capacity declined up to 7.04% over the summer training period (B3-B4) when NCAA rules limit athlete-coach communication. Aerobic capacity and FFM went unchanged (p \u3e 0.05) across the 2017 competitive season (B4-B6) despite the 2.03% reduction. PRACTICAL APPLICATIONS: As AC was shown to fluctuate throughout the annual training, it is recommended to monitory frequently assess physiological status. In Division I female soccer players, implementing a transition period after heavy training stresses could potentially positively influence AC. Additionally, concurrent training can have positive benefits to AC and FFM if appropriate rest is provided. Testing can ensure adequate rest and programmed training stress, where players will be able to maintain peak physiological fitness and therefore maintain a competitive advantage across the annual training cycle