The Pressor Response to Submaximal Cycle Ergometry While Using Aerodynamic Handlebars

This study hypothesized that changes in static shoulder loading while using aerobars during submaximal cycle ergometry would elicit a combined static and dynamic pressor response. Seven trained cyclists (x + SD: 22 ± 3 years, 77 ± 12 kg, 1.8 ± 1.1 m) rode a modified Monark cycle ergometer at three inclines (+ 5°, 0°, - 5° for five minutes each using aerobars at a power output (144 ±21 W) eliciting 60-65 % of each subject's age-predicted HR maximum (120 ± 4.9 bts min^-1). The positive to negative incline changes were designed to increase the static load experienced by the shoulder musculature. Mean HR, V_E, V0₂, and rectified EMC for the triceps brachii (TB), anterior (AD) and posterior deltoid muscles were computed over each minute <of each condition. All variables exhibited steady-state responses at + 5° and 0° inclines and nonsteady-state responses at - 5°. HIR, V0₂, and V_E correlated highly with EMC from AD (x_r = 0.75-0.79) and TB (x_r = 0.68-0.75) at - 5°, but only moderately correlated for HR at + 5° and 0° (x_r = 0.21 - 0.86). Y-intercepts for HR-VO₂ and V_E - V0₂ relationships shifted positively with increased static load. Thus, static loading of AD and TB may disassociate the HR - V0₂ relationship during submaximal cycle ergomettry and may be responsible for torso positioning preferences by time-trial cyclists.

Key words

Electromyography - time-trial cycling - torso angle