The identification of metabolic thresholds during upper- and lower-body exercise

Abstract

Purpose: The aim of this study was to examine and compare the peak respiratory and physiological variables, in both the upper- and lower- bodies of trained triathlete, analyse delta efficiency (%DE) values for both exercise modes as well calculating the %Wpeak at which the respiratory compensation point (RCP), lactate threshold (LT) and lactate turnpoint (LTP) were achieved in participants. Method: Seven trained male triathlete participants were selected for this study. There mean (±SD) values of age (yrs), height (m) and body mass (kg) were 25 (3.1), 1.83 (5.15) and 72.6 (5.19), respectively. Participants completed two incremental tests in both arm crank ergometry (ACE) and leg cycling (LC), with the required wattage increasing in increments throughout both test until participants reached exhaustion. A set crank rate of 75 rpm was enforced for ACE tests whilst participants were able to select their own cadence strategy for LC tests. Results: Mean (± SD) peak respiratory readings from both ACE and LC incremental tests were recorded, they indicated significantly higher peak values during LC than those of ACE. Significant values were found for HRpeak (184 ± 13 vs. 172 ± 26 bpm) and B [La] peak (9.5 ± 2.6 vs. 7.7 ± 2.8 mmol) for both (r= 0.97 and r= 0.93 respectively) modes of exercise. Significant mean values for respiratory exchange ratio peaks (RER) for both ACE and LC (1.05 ± 0.07 and 1.08 ± 0.07, respectively) were found (>0.05). The attainment of thresholds at %Wpeak were found to be significantly higher in LC than ACE (%Wpeak LT- 67.74 ± 8.71 and 41.28 ± 8.47, LTP- 79.19 ± 11.03 and 63.08 ± 7.97, respectively), additionally no significant relationship was shown between attainment of thresholds in both LC and ACE at %Wpeak. However significant mean values (>0.05) were found for the %Wpeak RCP achieved during LC and ACE (78 ± 5 and 76.52 ± 9.68, respectively). The %DE during both tests was found to be significantly higher during LC in comparison to ACE (22.5 ± 2.9 and 15 ± 4.11, respectively), additionally no significance correlation was found to exist between the two exercise modes. Findings: The results of this study show that higher peak power, heart rates, B [La] and respiratory readings are attained during LC than ACE, in additional LC proved to be significantly more efficient during the incremental protocol in comparison to xiii ACE. Triathletes achieved the RCP, LT and LTP at a higher %Wpeak during LC than during ACE indicating that triathletes may have been more highly trained in the LC mode of exercise than ACE therefore they were able to delay relative attainment of thresholds for longer. The findings demonstrate higher mean peak, efficiency and absolute values produced during lower body exercise than those of upper body exercise giving coaching/ researchers a further insight into the physiological values produced by multidisciplinary (cross) trained athletes, these can be used in future and taken into consideration during construction of training plan for these specific types of athletes.