The Effect Of Acute Chronic Training Load Ratio On Daily Stress, Fatigue, And Soreness Level In A Ncaa Division 1 Soccer Players

Abstract

PURPOSE: To investigate the effect of acute chronic work load ratio (ACWL) on daily stress, fatigue, and soreness throughout a collegiate men’s soccer season. METHODS: Sixty-four male collegiate soccer players (mean±SD; age, 20±2y; body mass, 77.3±6.7kg; height, 179.9±6.4cm; VO2max, 53.0±5.0ml•kg-1•min-1) participated in this study, which took place during the 2016 and 2017 NCAA soccer season. During each training session and match, players donned a heart rate and GPS enabled chest strap to measure training impulse (TRIMP). Daily stress, fatigue, and soreness levels were collected using 1 to 10 Likert-scales before each training session and match. ACWL was calculated for TRIMP using the ratio of the previous 7-day average to the previous 28-day average. ACWL values were categorized into three groups: low, ACWL<0.8; medium, 0.8≦ACWL<1.5; high, ACWL≧1.5. Stress, fatigue, soreness levels were transformed to corresponding z-scores to account for individual differences. One-way ANOVA with Tukey pairwise comparison was used to assess stress, fatigue, soreness levels in different ACWL groups. Mean difference (MD), 95% confidence interval (95%CI) and effect size (ES), suggested by Cohen were calculated. RESULTS: Stress levels were significantly higher when ACWL was high compared to low (MD=0.47, 95%CI=0.34-0.60, ES=0.44) and medium (MD=0.37, 95%CI=0.25-0.48, ES=0.28) (p=0.001). Fatigue levels were significantly higher when ACWL was high (0.36±1.15) compared to low (MD=0.56, 95%CI=0.42-0.69, ES=0.55) and medium (MD=0.38, 95%CI=0.26-0.49, ES=0.36) (p=0.001). Fatigue levels were also significantly higher when ACWL was medium compared to low (MD=0.18, 95%CI=0.07-0.29, ES=0.20, p=0.001). Soreness level was significantly higher when ACWL was high compared to low (MD=0.51, 95%CI=0.37-0.64, ES=0.49) and medium (MD=0.38, 95%CI=0.26-0.50, ES=0.31) (p=0.001). CONCLUSIONS: ACWL could impact daily stress, fatigue, and soreness levels. A large change in ACWL (≧1.5) was associated with moderate to large changes in stress, fatigue, and soreness levels compared to low ACWL. Thus, ACWL may be used to manage athlete’s daily stress, fatigue, and soreness levels and optimize periodization. However, other factors should be also considered, such as sleep.