title: Running economy is negatively related to sit-and-reach test performance in international-standard distance runners.
abstract: The purpose of this study was to investigate the relationship between running economy (RE) and lower body flexibility. Thirty-four international-standard male distance runners (mean +/- s, age 27 +/- 5 years; body mass 64.9 +/- 4.2 kg; VO(2)max 72.8 +/- 3.7 ml x kg(-1) x min(-1)) gave written consent to participate in this study. The subjects performed an incremental treadmill test for the assessment of RE, lactate threshold and VO(2)max, and the sit-and-reach test was used to assess their general lower body and trunk flexibility. Running speeds below the lactate threshold were used to explore the relationship between running economy and sit-and-reach test performance. At 16.0 km x h(-1), the VO(2) was 50.6 +/- 3.7 ml x kg(-1) x min(-1) (range: 44.2 to 57.1 ml x kg(-1) x min(-1)). Pearson product moment correlation coefficients revealed no significant relationships between aerobic demand at 16.0 km x h(-1) and age (r = - 0.19), height (r = 0.15), body mass (r = - 0.18), or VO(2)max (r = - 0.004). However, there was a highly significant relationship between aerobic demand at 16.0 km x h(-1) and the sit-and-reach test score (r = 0.68; p < 0.0001). These results suggest that the least flexible runners are also the most economical. It is possible that stiffer musculotendinous structures reduce the aerobic demand of submaximal running by facilitating a greater elastic energy return during the shortening phase of the stretch-shortening cycle.
authors.affiliation: Department of Exercise and Sport Science, Manchester Metropolitan University, Alsager, United Kingdom. a.m.jones@mmu.ac.uk
authors.forename: A M
authors.initials: AM
authors.lastname: Jones
mesh_terms: D000328:Adult; D005080:Exercise Test; D006801:Humans; D007773:Lactates / Q000097:blood; D007866:Leg / Q000502:physiology*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D018583:Pliability; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012420:Running / Q000502:physiology*; D013647:Task Performance and Analysis
chemical_list: D007773:Lactates