Effect of ascent to a moderate altitude on muscle performance in different strength manifestations

Altitude training plays an important role in the physical preparation of athletes around the world with the expectation of improving sea level performance. Traditionally, research about altitude training has focused on endurance performance and related parameters (e.g., maximum oxygen consumption, total haemoglobin mass, etc). The effectiveness of altitude training strategies in the development of endurance performance is generally recognised (Bonetti & Hopkins, 2009). However, the effect of altitude training on the performance of explosive actions remains virtually unexplored. Swimmers are amongst the athletes who use altitude training most often. Therefore, it is reasonable to explore the effects of a traditional altitude training camp held at moderate altitude (2320 m asl) on swimming start performance, which is the swimming skill most dependent on explosive force and lower-body muscular power. The main objective of the present Doctoral Thesis was to examine the effect of altitude training on unloaded and loaded jump squat and swimming start performance. In addition, the present research work also aimed to refine the methodology of strength testing and to explore the relationship between different strength manifestations and swimming start performance. To achieve these purposes, different groups of high level athletes (swimmers from the Slovenian national team, swimmers from the Spanish junior national team, and athletes from different combat sports) participated in the nine studies compiled in the present Doctoral Thesis. Along these studies, the performance of explosive actions such as vertical jumps, bench press, and swimming start performance were assessed in normoxia and after the acute and chronic exposure to a moderate altitude (Studies V-IX). Additionally, the simultaneous use of a force platform and a linear velocity transducer allowed us to refine the methodology of loaded vertical jump testing (Studies I-II). Finally, we studied the force derived variables during the push-off phase and swimming start time in swimming starts to identify the best predictors of swimming start performance (Studies III-IV). The primary findings of the present Doctoral Thesis revealed that: (I) the maximum velocity of the bar can be used to predict vertical jump height; (II) the linear velocity transducer is a valid measurement method to assess loaded squat jump performance; (III) the horizontal take-off velocity is the push-off variable most related with swimming start time; (IV) the peak velocity reached during the loaded squat jump proved to be the best indicator of swimming start time; (V) squat jump and bench press performance improve after an acute ascent to altitude; (VI) swimmers that are able to jump higher with additional loads relative to their body weight have a faster swimming start time. In addition, an improvement in vertical jump height following a short-term training program can be used to predict changes in swimming start performance; (VII) the implementation of a power-oriented resistance training during a stay at moderate altitude might enhance the performance of explosive actions such as the loaded squat jump and swimming start time; (VIII) the increase in the maximal mechanical capabilities of leg extensors muscles to generate power after an acute ascent to terrestrial altitude is caused by an increase in the theoretical maximal velocity with no significant changes for maximum force capabilities; and (IX) a typical living high – training high strategy oriented towards the improvement of general strength and endurance capacity has trivial effects on muscular function.