Energetics of swimming at maximal speeds in humans

Abstract

The energy cost per unit of distance (Cs, kilojoules per metre) of the front-crawl, back, breast and butterfly strokes was assessed in 20 elite swimmers. At sub-maximal speeds (v), Cs was measured dividing steady-state oxygen consumption (VO2) by the speed (v, metres per second). At supra-maximal v, Cs was calculated by dividing the total metabolic energy (E, kilojoules) spent in covering 45.7, 91.4 and 182.9 m by the distance. E was obtained as: E = Ean + alphaVO2maxtp - alphaVO2maxtau(1 - e(-(tp/tau))), where Ean was the amount of energy (kilojoules) derived from anaerobic sources, VO2max litres per second was the maximal oxygen uptake, alpha( = 20.9 kJ x 1 O2(-1)) was the energy equivalent of O2, tau (24 s) was the time constant assumed for the attainment of VO2max at muscle level at the onset of exercise, and tp (seconds) was the performance time. The lactic acid component was assumed to increase exponentially with tp to an asymptotic value of 0.418 kJ x kg(-1) of body mass for tp> or =120 s. The lactic acid component of Ean was obtained from the net increase of lactate concentration after exercise (delta[La]b) assuming that, when delta[La]b = 1 mmol x 1(-1) the net amount of metabolic energy released by lactate formation was 0.069 kJ x kg(-1). Over the entire range of v, front crawl was the least costly stroke. For example at 1 m x s(-1), Cs amounted, on average, to 0.70, 0.84, 0.82 and 0.124 kJ x m(-1) in front crawl, backstroke, butterfly and breaststroke, respectively; at 1.5 m x s(-1), Cs was 1.23, 1.47, 1.55 and 1.87 kJ x m(-1) in the four strokes, respectively. The Cs was a continuous function of the speed in all of the four strokes. It increased exponentially in crawl and backstroke, whereas in butterfly Cs attained a minimum at the two lowest v to increase exponentially at higher v. The Cs in breaststroke was a linear function of the v, probably because of the considerable amount of energy spent in this stroke for accelerating the body during the pushing phase so as to compensate for the loss of v occurring in the non-propulsive phase.

A preliminary study on the relationship between energy expenditure and skin temperature in swimming

“…Previous studies have demonstrated that front crawl and backstroke techniques were more economical than butterfly and breast stroke and that front crawl was more economical than backstroke at slower and maximal speeds [9,13,14]. Our results are in line with these studies and confirmed higher energy expenditure values during backstroke test than during front crawl test.…”

Observação e caracterização técnica em natação pura desportiva: 200 m bruços

“…The lactate concentrations obtained were similar to previous studies for 200 m distances 26,[45][46][47] , corroborating that the 200 m event presents significant anaerobic contribution. The decrease pre-sented in SV, SF and Sl agree with the results presented by previous studies 3,9,12,7,48 , when refer that in the breaststroke technique there is increase in SV associated with increase in SF, but higher decrease in Sl relatively to other swimming styles 9 , corroborating alteration in the technique during the 200 m 3 .…”

The underwater environment: cardiopulmonary, thermal, and energetic demands

“…Maximal cardiac output, heart rate, blood flow, and oxygen transport and anaerobic threshold and power output are ϳ15% lower during immersion than in air, even in thermoneutral water (75). During underwater swimming with fins the V O 2max is significantly less than in air and surface swimming (17). In addition, the energy cost of underwater fin swimming is influenced by the types of fins worn, which in turn tends to vary with sex and the technical ability of the diver (83,84).…”