Arm insulation and swimming in cold water.
To test whether adding insulation to the arms would improve cold water swimming performance by delaying swimming failure (SF). Novice (n = 7) and expert (n = 8) swimmers, clothed and equipped with a personal flotation device, each performed two trials in a swimming flume filled with 10 degrees C water. During free swimming (FS), subjects performed swimming until failure, followed by the Heat Escape Lessening Posture. In free swimming with additional insulation (FSA), subjects wore custom-fitted armbands. Trials ended when rectal temperature decreased to 34 degrees C or after 2 h of immersion. Measurements included: rectal and skin temperatures, heat flow, and various appraisals of swimming performance. FSA was thermally advantageous versus FS. Rectal temperature cooling rates during swimming (dT/dt Swim) were faster for FS compared to FSA (0.050 +/- 0.007 degrees C min(-1) vs. 0.042 +/- 0.006 degrees C min(-1), P < 0.01). Armbands maintained arm skin temperature about 10 degrees C warmer, for approximately 70 min (P < 0.001). Although additional insulation did not greatly improve physical performances, video analysis showed that swimming technique in FSA was maintained 10-15% better than in FS between minutes 30 and 50 (P < 0.001). SF was achieved in 5/30 trials, with increases in stroke rate (6.6 str min(-1)) and decreases in stroke length (0.24 m str(-1)) observed. In this simulation of cold water swimming survival, equipping subjects with neoprene armbands appears to have partially preserved muscle function, but with unimpressive effects on overall performance. SF is a complex entity, but is evidently related to both triceps skinfold and arm girth.
Lounsbury
David S
DS
Exercise Sciences Department, University of Toronto, Toronto, ON, Canada, M5S 1A1.
Ducharme
Michel B
MB
D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D000886:Anthropometry; D001132:Arm / Q000098:blood supply / Q000502:physiology*; D001823:Body Composition / Q000502:physiology; D001827:Body Height / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D003080:Cold Temperature; D005260:Female; D006801:Humans; D007101:Immersion / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D011481:Protective Clothing; D011597:Psychomotor Performance / Q000502:physiology; D012044:Regression Analysis; D012881:Skin Temperature / Q000502:physiology; D016019:Survival Analysis; D013550:Swimming / Q000502:physiology*