The biomechanics of and physiological responses to vertical treadmill exercise.

The vertical treadmill is a novel exercise mode designed for the physical conditioning of athletes. It requires a running action in a recumbent posture on a vertically hung, non-motorised treadmill whilst the limbs are supported with overhanging resistance cables. To the author's knowledge, there has been no research on the vertical treadmill. Therefore, the aim of this thesis was to identify whether the vertical treadmill is an appropriate tool for physical conditioning. To achieve this aim there were four objectives: 1) identify the lower limb kinematics; 2) identify the neuromuscular recruitment patterns during vertical treadmill exercise in different postures and intensities; 3) identify the acute physiological responses to vertical treadmill exercise at varying intensities and 4) identify the adaptations to a training intervention on the vertical treadmill in a physically active population. The kinematic and neuromuscular recruitment patterns during vertical treadmill exercise revealed that irrespective of posture and intensity, the hamstrings and gastrocnemius muscles were active to draw the leg downwards against the resistance cables and the rectus femoris and tibialis anterior were active in the upward phase. The vastii muscles were not active. The 40° and 70° postures were similar and both differed from the supine posture. The physiological responses to submaximal and maximal vertical treadmill exercise in the 40° posture revealed a lower maximum heart rate and VO2peak when compared with conventional treadmill running. The onset of blood lactate (2 mmol.L[-1]) during very light vertical treadmill exercise and a high maximal lactate identified the vertical treadmill as a predominantly anaerobic exercise. In light of this, the effect of a 6-week sprint interval training (SIT) (4-6, 30 s all-out efforts with 4.5 min recovery, 3 times per week) on VO2max, maximum anaerobic running power and responses to submaximal running on a conventional treadmill were compared with SIT performed over ground (20 m shuttle sprints) and control group. The key findings of this study were that over ground and vertical treadmill SIT increased the anaerobic running power by 4% each and that VO2max, increased by 4% and 6%, respectively. No differences were found in submaximal running responses. This evidence indicates that vertical treadmill can be used as a low-impact conditioning tool without detriment to running performance. The physiological underpinnings for the improvement in running performance should be the focus of future research.