The effect of strength training at the same time of the day on the diurnal fluctuations of muscular anaerobic performances.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 21993020 · doi:10.1519/JSC.0b013e31821d5e8d
What was done
Thirty participants were randomly assigned to a morning training group (07:00-08:00 hours, n = 10), an evening training group (17:00-18:00 hours, n = 10), or a non-training control group (n = 10). Both training groups underwent 8 weeks of progressive lower-extremity resistance training 3 times per week. Anaerobic performance (squat jump, countermovement jump, Wingate test, and 1-repetition maximum for leg extension, leg curl, and squat) was tested in both morning and evening sessions before training and 2 weeks after the 8-week intervention.
What was found
Prior to training, all groups showed a significant increase in performance from morning to evening tests (ca. 2.84-17.55% across all tests). Following training, the diurnal variations in anaerobic performance were blunted in the morning training group, with no significant difference in muscular power or strength between morning and evening tests. Diurnal variations persisted in the evening training group and control group. Specific absolute values, standard deviations, and exact p-values were not reported in the abstract.
Why it matters
Adaptations to resistance training display time-of-day specificity. Athletes competing in morning events may eliminate standard morning anaerobic performance deficits by consistently scheduling their workouts in the morning.
Limits
The sample size is small (10 subjects per group). The abstract does not specify participant sex, age, baseline fitness levels, or whether sleep and nutrition were standardized. Testing occurred 2 weeks after the training period rather than immediately, and detailed numerical metrics were not provided.
Cited by
- supports Transitioning resistance training from the late afternoon or evening to the morning causes an initial drop in performance that resolves within a couple of weeks.