Context:

Overreaching can be beneficial, but there is a risk of overtraining.

Objective:

To investigate the difference in sleep efficiency between overreached and nonover-reached swimmers.

Design:

Repeated-measures, between-subjects. Swimmers were determined to be overreaching if 2 or more of their consecutive weekly swim times increased by 5% or more from baseline.

Participants:

9 competitive high school and university sprinter swimmers.

Intervention:

24-h wrist actigraph.

Main Outcome Measure:

Sleep efficiency as measured by the actigraph.

Results:

There was a significant difference in sleep efficiency on night 1 between the overreached and nonoverreached swimmers (P = .008), as well as in their times after averaging over all 5 trials and adjusting for baseline (P = .016). By the fourth swim trial, the overreached swimmers had significantly slower swim times than those of the nonoverreached swimmers (P = .001).

Conclusions:

Sleep efficiency shows potential as an objective, noninvasive predictor and monitor of overreaching in swimmers.