Effect of fatigue on stroking characteristics in an arms-only 100-m front-crawl race

• Published in: Medicine and science in sports and exercise 2006-09, Vol.38 (9), p.1635-1642
• Main Authors: TOUSSAINT, Huub M, CAROL, Arnoud, KRANENBORG, Hilke, TRUIJENS, Martin J
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Arm - physiology; Biological and medical sciences; Biomechanical Phenomena; Fundamental and applied biological sciences. Psychology; Humans; Male; Muscle Fatigue - physiology; Muscle Strength - physiology; Muscle, Skeletal - physiology; Physical Exertion - physiology; Space life sciences; Swimming - physiology; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 0195-9131; 1530-0315
• DOI: 10.1249/01.mss.0000230209.53333.31

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. 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. 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. 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.