The physiological demands of 'hiking' on dinghy sailors

Vogiatzis, Ioannis (1995) The physiological demands of 'hiking' on dinghy sailors. PhD thesis, University of Glasgow.

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Abstract

The purpose of the studies presented in this thesis was to combine on-water and off-water measurements in order to investigate the physiological demands of the major physical challenge in dinghy sailing: the '"hiking" effort, which is performed in order to counterbalance a dinghy in moderate and stronger winds. This purpose was achieved by:-1) Investigating the course of a number of physiological variables under actual sailing conditions. 2) Using this information to closely simulate sailing in the laboratory. 3) Investigating in the laboratory a number of physiological variables which could not be studied under real sailing conditions. On the basis of the resultant findings sailing-specific training regimes were administered to sailors to assist them in maximising hiking performance. The use of portable telemetry allowed investigation of a number of cardiorespiratory parameters during actual sailing conditions. A series of on- water measurements revealed that aerobic capacity is only moderately taxed in dinghy sailing (39.5 +/- 6.0 % VO2 max at wind-speeds of between 4 and 12 ms-1 in 'Laser' dinghies) whereas the cardiac and respiratory functions are taxed proportionally more, thus leading to a marked tachycardia (74 +/- 10 % HR max) and hyperventilation (VE/VO2: 26.8 +/- 1.6). Blood lactate concentration measurements suggested that anaerobic metabolism plays an increasing role in stronger winds. The causes of tachycardia and hyperventilation were further investigated during simulated hiking. The latter investigation offered evidence of a direct association between the onset and magnitude of fatigue in quadriceps muscle groups and the cardiovascular and ventilatory drives. The development of muscular fatigue, which was mirrored in the progressive increase in the quadriceps EMG activity, is likely to have led, directly or indirectly, to the progressive tachycardia and hyperventilation. These changes in HR, VE and EMG activity occurred in the absence of changes in the lactate concentration. Further EMG measurements carried out during simulated hiking suggests that fatigue in quadriceps is due to the high degree to which these muscles were activated during hiking (approximately 30 % maximum) and that it seems reasonable to believe that local muscular fatigue is the most likely factor to limit hiking performance. Although an improvement in hiking performance was achieved after the administration of different training regimes, the present findings offer no conclusive evidence of the mechanisms responsible for resisting fatigue in quadriceps and thus maximising hiking performance. It was concluded that training regimes for sailors should not emphasise aerobic fitness but the local static endurance of the thigh muscles.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: N C Spurway
Keywords: Kinesiology
Date of Award: 1995
Depositing User: Enlighten Team
Unique ID: glathesis:1995-70952
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 08 May 2019 09:21
Last Modified: 08 May 2019 09:21
URI: http://theses.gla.ac.uk/id/eprint/70952

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