Sprint running kinetics and kinematics in youth
The purpose of this thesis was to investigate sprint kinetics and kinematics in youth with regards to maturation and to test how participants in different maturity status react to resisted-strength type conditioning.
Initially, two literature reviews described methodologies to assess youth sprint performance, their reliability, resulting performance data and the current scientific knowledge on different training methods on running sprint times in male youth. It was presented that a) a non-motorized is able to measure running mechanics, however is underutilized in performance assessment and b) pre-peak height velocity (PHV) children benefit most from training requiring high levels of neural activation, while post-PHV participants responded more favorable to training modes that targeted both neural and structural development.
The consecutive series of cross sectional studies investigated methodological and analytical issues with the non-motorised treadmill and how sprint mechanics at maximum sprint velocity change with maturation. It was seen that a non-motorised treadmill is a reliable measurement device to assess sprint mechanics. Additionally, a 15% body mass threshold is the most appropriate relative threshold to analyse data from the non-motorise treadmill. The key findings with regards to the influence of maturation on sprint mechanics at maximum velocity was that sprint performance improve throughout the athletes development with age (speed, concentric power), however important determinants of sprint performance (step length, step frequency, horizontal force, horizontal power, concentric time) change significantly at the time of PHV and furthermore at the stage of post-PHV (contact time, eccentric time and relative vertical force).
The thesis concluded with a training study investigating the effect of resisted sled towing on sprint running times. The mid-/ and post-PHV participants responded better to the same relative resisted sprint load and were able to improve sprint performance, while the pre-PHV athletes did not improve sprint performance.