Sprint Acceleration Research Articles

Blood gas changes during incremental and sprint exercise

We investigated and compared arterial blood gas and ventilatory changes during rapid acceleration sprint and during incremental treadmill exercise. Seven clinically normal racehorses completed standardised incremental exercise tests and rapid acceleration tests at speeds calculated to elicit 115% VO2max. Arterial oxygen tension decreased (P < 0.001) between 15 s (mean +/- s.d. 103.8 +/- 14.3 mmHg) and 30 s (85.0 +/- 7.7 mmHg) after the onset of rapid acceleration exercise, but did not change significantly during the remainder of the sprint. This was accompanied by an increase in PaCO2 of 5.9 mmHg (P < 0.05). Despite reductions in SaO2 during exercise, CaO2 did not change due to increases in haemoglobin concentration. Heart rate increased rapidly (P < 0.001) during the first 15 s of exercise and thereafter remained constant. The mean maximum speed during the incremental test (11.4 +/- 0.5 m/s) was not significantly different to the speed calculated to elicit 115% VO2max during the sprint test (12.2 +/- 0.8 m/s). The mean peak HR and Hb during the sprint test were significantly less than during the incremental test. However, there were no significant differences in the maximum or minimum values achieved for other variables. We conclude that rapid acceleration exercise is accompanied by rapid changes in blood gas variables, reaching steady state within 45 s. Blood gas responses during the simpler incremental test describe maximal changes during high-intensity sprint exercise.

Dynamics and biomechanics on start and accelerated phase of a sprint

Overground sprint studies have shown the importance of net horizontal ground reaction force impulse (IMPH) for acceleration performance, but only investigated one or two steps over the acceleration phase, and not in elite sprinters. The main aim of this study was to distinguish between propulsive (IMPH+) and braking (IMPH−) components of the IMPH and seek whether, for an expected higher IMPH, faster elite sprinters produce greater IMPH+, smaller IMPH−, or both.Nine high-level sprinters (100-m best times range: 9.95–10.60 s) performed 7 sprints (2×10 m, 2×15 m, 20 m, 30 m and 40 m) during which ground reaction force was measured by a 6.60 m force platform system. By placing the starting-blocks further from the force plates at each trial, and pooling the data, we could assess the mechanics of an entire “virtual” 40-m acceleration.IMPH and IMPH+ were significantly correlated with 40-m mean speed (r=0.868 and 0.802, respectively; P<0.01), whereas vertical impulse and IMPH− were not. Multiple regression analyses confirmed the significantly higher importance of IMPH+ for sprint acceleration performance. Similar results were obtained when considering these mechanical data averaged over the first half of the sprint, but not over the second half. In conclusion, faster sprinters were those who produced the highest amounts of horizontal net impulse per unit body mass, and those who “pushed more” (higher IMPH+), but not necessarily those who also “braked less” (lower IMPH−) in the horizontal direction.

A Microcomputer-Based Timer and Data Acquisition Device for Measuring Sprint Speed and Acceleration in Cursorial Animals

A Microcomputer-Based Timer and Data Acquisition Device for Measuring Sprint Speed and Acceleration in Cursorial Animals

Predicting sprint dynamics from maximum-velocity measurements

Following Furusawa et al., the linearized Hill force-velocity curve is used to derive dimensionless position-time and velocity-time equations for sprint acceleration. Arguments are presented to show that the horizontal force is essentially constant, and thus only the maximum velocity v 0 is required to predict the runner's performance. Experimentally, 12 different stride parameters are presented for each of 43 individuals. Regression equations show that stride length S 0 is well correlated with v 0. Theory is compared with the experiments of Best and Partridge and also the 1984 world records for sprinters. One practical application of this work is that track coaches can now obtain both force and peak-velocity information by recording distance and elapsed time for two or more intermediate- length dashes. Data from Evelyn Ashford, world record holder in the 50-yd, the 60-yd, and the 100-m dash show that h =0.742 mg and ν 0=10.78 m/sec. The dimensionless position number gx ν 2 0 and the dimensionless time number gt ν 0 allow us to plot all individuals on the same graph for sprints less than the fatigue distance, showing adequate agreement between theory and experiment.