TIME COURSE OF THE EFFECTS OF STATIC STRETCHING ON CYCLING ECONOMY ALYSON E. WOLFE,LEE E. BROWN,JARED W. COBURN,ROBERT D. KERSEY, AND MARTIM BOTTARO Human Performance Laboratory, Department of Kinesiology, California State University, Fullerton, California ABSTRACT Wolfe, AE, Brown, LE, Coburn, JW, Kersey, RD, and Bottaro, M. Time course of the effects of static stretching on cycling economy. J Strength Cond Res 25(11): 2980–2984, 2011—Stretching has been implemented as part of the warm-up before physical events and widely thought to promote increased sport performance and decreased injury risk. However, recent research has concluded that static stretching before many exercises inhibits acute power, strength, and sprinting performance. There is little research examining the time course of these effects on moderate intensity cycling. The purpose of this study was to examine the time course of static stretching on cycling economy. The subjects consisted of 5 men and 5 women highly trained endurance cyclists. The first of 3 visits was baseline testing of their cycling _ VO 2 max. The second and third visits were either stretching or no stretching before a 30-minute stationary ride at 65% of their _ VO 2 max. The stretching condition consisted of four 30-second repetitions of 5 stretches with an average total stretching time of 16 minutes. _ VO 2 demonstrated a significant condition by time interaction with the 5-minute time point being significantly less in the non- stretching condition (32.66 6 5.35 mlÁkg 21 Ámin 21 ) than stretching (34.39 6 5.39 mlÁkg 21 Ámin 21 ). No other time points were different. Our results demonstrate that static stretching yielded an acute increase in submaximal _ VO 2 ; therefore, coaches and highly trained endurance cyclists should exclude static stretching immediately before moderate intensity cycling because it reduces acute cycling economy. KEY WORDS oxygen, sex, exertion INTRODUCTION S tretching has long been stressed as an important part of physical training and is thought to promote increased sport performance and decreased risk of injury by increasing range of motion (2,7,8). How- ever, recent research has concluded that static stretching before many exercises may inhibit acute power, strength, and sprinting performance (1,2,4,5,12,14,15,17,19,21,23,27). One theory behind these decreases in sport-related factors is that stretching causes a decrease in musculotendon stiffness and creates a reduction in stored elastic energy (4). This acute stretch–induced reduction, and the reductions seen with increased flexibility, creates a significant inverse relationship between stretching, flexibility, and performance (3,7,22). Stored elastic energy in the hip and leg musculature may allow greater energy economy in the muscles and tendons during sport performance (5,24). It has been suggested that runners with tighter musculotendinous structures require less work from muscles at a submaximal velocity because of the use of stored elastic energy (16,20). This tightness may lead to greater economy and increased performance of endurance-trained running athletes. However, because cycling takes place through a limited range of motion, does not use the same amount of elastic energy as running, and does not require the same activation of stabilizing muscles as running does, these factors may not be determinants of the effects of stretching on the mechanical properties of muscle during cycling. Endurance athletes require optimal economy to maintain the intensity of exercise for long periods of time, which leads to improved athletic performance (3,6,7,11,13,16,20,24,26,28). Economy refers to the volume of oxygen ( _ VO 2 ) required to maintain work at a given speed (9,10,14,26). The importance of stored elastic energy to economy is substantial because its use has been shown to contribute as much as 40–50% of the energy required during a distance event (22). In the inverse relationship between flexibility and perfor- mance, sex differences also play a role (3,7,8,13,18,22) with previous research on distance runners finding that men were 6–7% more economical than were women at a given velocity (13). Considering that men have consistently demonstrated less flexibility than women have suggests that this mechanical difference could contribute to the observed sex differences in running economy (13,18,22). At this time, there is a paucity of research that has investigated how long the effects of stretching may last during cycling and any differences between men and women. We hypothesize that static stretching will reduce muscular stiffness for a short time, leading to decreased cycling economy. Therefore, the purpose of this study was to investigate the time course of the effects of static stretching on cycling economy. Address correspondence to Lee E. Brown, leebrown@fullerton.edu. 25(11)/2980–2984 Journal of Strength and Conditioning Research Ó 2011 National Strength and Conditioning Association 2980 Journal of Strength and Conditioning Research the TM Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.