Sleep restriction and serving accuracy in performance tennis players, and effects of caffeine.
Level 2 - randomized trial
Individual randomized crossover trials
PubMed 23916998 · doi:10.1016/j.physbeh.2013.07.002
What was done
Two experimental crossover studies tested the effect of acute sleep restriction (5 hours of sleep, representing a 33% reduction) versus normal sleep on serving accuracy in semi-professional tennis players. Testing occurred between 14:00 and 16:00 and consisted of 40 serves into a 1.8 m × 1.1 m target box. Study 1 included 16 players (8 men, 8 women) in a counterbalanced within-subject design. Study 2 included 12 different players (6 men, 6 women) in a 3-condition Latin square design testing normal sleep, sleep restriction plus placebo, and sleep restriction plus 80 mg caffeine in a sugar-free drink given double-blind 30 minutes before testing.
What was found
Both studies showed significant impairments in serving accuracy after sleep restriction. In Study 2, 80 mg of caffeine had no beneficial effect. In Study 1, women had significantly poorer serving accuracy across all conditions, with non-significant indications in both studies that women were more impaired by sleep restriction than men. The abstract reports no exact numerical scores, error margins, or effect sizes.
Why it matters
This study shows that moderate acute sleep loss directly degrades fine psychomotor accuracy and judgement in sport skills, and that a modest dose of caffeine is insufficient to counteract these deficits.
Limits
Sample sizes were very small (16 in Study 1, 12 in Study 2). The research evaluated only a single night of partial sleep restriction and a single modest caffeine dose (80 mg), leaving open the questions of chronic sleep loss, dose-response relationships, and generalizability to match play. No numerical values or p-values are reported in the abstract.
Cited by
- partial Restricting semi-professional tennis players to 5 hours of sleep impaired their serving accuracy by approximately 35%, and caffeine only recovered about one-third of that lost accuracy.