Effect of fatigue on stroking characteristics in an arms-only 100-m front-crawl race.
OBJECTIVE
Race analyses during swimming provide information on the time-dependent values of, among other variables, a swimmer's clean swimming speed (v), stroke rate (SR), and stroke length (SL). The effect of fatigue on changes in v, SR, and SL was investigated.


METHODS
Lap-averaged values of v, SR, and SL while swimming 100 m all out with arms only (trial 1) were related to the decline in mechanical power output measured during an all-out 100-m swim on the MAD system (trial 2), with legs immobilized in both trials.


RESULTS
Swimming a 100-m front-crawl sprint using arms only led to a significant 24% decrease in lap-averaged mechanical power output (from 200 to 153 W, P < 0.01). This reduction in power-generating capacity led to a 12.4% decrease in v when lap 1 was compared with lap 4 (from 1.69 to 1.48 m x s(-1), P < 0.01). SR declined throughout the race by 10.6% from 0.85 Hz (lap 1) to 0.76 Hz (lap 4, P < 0.05). Analysis revealed that this decrease in SR was linearly related to the decrease in v. The reduction in SR reflected the reduced propulsive force required to overcome the v-dependent, and therefore lower, drag.


CONCLUSIONS
Decreases in swimming speed throughout a 100-m front-crawl race are the result of decreases in the power-producing capacity of the swimmer (fatigue). This fatigue-induced reduction in swimming speed will lead to a reduction in drag. The SR seems to be accommodated to this reduced power output capacity and concomitant diminished propulsion requirements.
Toussaint
Huub M
HM
Academy for Physical Education, University of Professional Education, Amsterdam, The Netherlands. H_M_Toussaint@fbw.vu.nl
Carol
Arnoud
A
Kranenborg
Hilke
H
Truijens
Martin J
MJ
D000293:Adolescent; D000328:Adult; D001132:Arm / Q000502:physiology*; D001696:Biomechanical Phenomena; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D013550:Swimming / Q000502:physiology*