Edinburgh Napier University

  Purpose: To, one, investigate the anatomical and physiological attributes of Downhill mountain bike athletes and, two, to determine the influence of these inherent physiological attributes on Downhill race performance. Methods: The study consisted of two testing components; laboratory- and field-based testing. Laboratory study: An anthropometric profile was determined from seven trained and competitive DH athletes (age 21 ± 5 years). Peak power output and time to peak power were determined by six, 6-second maximal sprints, performed on an SRM stationary ergometer. Cadence was restricted during five sprints (60, 80, 100, 120 and 140 rpm) to determine optimal cadence for achieving peak power. Field study: Twelve trained and competitive DH athletes (age 20 ± 5 years) performed two timed runs of a National Championship DH course. Heart rate was recorded and two GPS units (attached to the bicycle and helmet) recorded speed (kmhr¬¬-1), distance (m), time (seconds) and impacts (g). Results: Laboratory study: DH cyclists have predominantly mesomorphic somatotypes (mean somatotype values, 2.1,4.7,3.0) with a mean sum of 8 skinfolds, 68.7 ± 19.8 mm. Sprint testing revealed peak power output (23.36 ± 2.12 Wkg-1) was achieved at restricted cadence of 110 rpm and time to peak power output was 1.5 ± 0.9 seconds. Field study: DH race run time was 178.57 ± 12.10 seconds. Analysis showed two areas of the DH course to affect overall performance; start of the race and the technical section (r = 0.76 and r = 0.94, respectively). Correlation equations identified mean distance travelled in the first 5, 6 and 10 seconds of the race (22.0 ± 2.8 m, 30.5 ± 3.1 m and 70.4 ± 6.2 m, respectively) had a positive influence (p < 0.05) on overall run time. Peak (28.5 ± 3.4 kmhr¬¬-1) and mean (16.8 ± 1.9 kmhr¬¬-1) speed during the technical section (course Section 4) had a positive effect on performance time (p < 0.05) Correlation equations between laboratory and field-testing identified peak power output and time to peak power had a positive influence (p < 0.05) on the start of the race (first 15 seconds) and thus, overall performance. Conclusions: DH is a dynamic, high intensity cycling discipline with many factors influencing performance. Whilst technical skills are essential, results identified that physiological parameters (peak power output and time to peak) can positively affect the start section of a run (p = 0.049 and p = 0.032), and in turn, overall race time. Therefore, training to improve these measures would be appropriate for DH athletes.