Abstract Rationale Cardiopulmonary fitness aerobic capacity, an important determinant of mortality, can be improved by aerobic exercise training provided the load exceeds that encountered during daily life. Specificity of the exercise stimulus relative to the goal is important. Aerobic capacity is determined by the resistance to oxygen flow from the lungs to the muscles. Specifically improving flow at any step without compromising the other steps will improve the sum. For example, partitioned training emphasizes the muscle (peripheral) stimulus in patients with chronic respiratory disease. Conversely increasing the number of muscles, each at low intensity, to total the same aerobic demand (central) can avoid peripheral limiting factors. In this study we aimed to ascertain in healthy individuals whether we could demonstrate a practically significant increase in exposure (endurance time) to an aerobic training central stimulus by distributing the demand among more muscle groups compared with conventional cycle exercise. We added arm cycling to a reduced leg cycling demand to maintain the total central demand. We hypothesized that tolerance of high intensity aerobic exercise at the same aerobic intensity (central stimulus) would be greater when more muscles were used (legs and arms) compared to less muscles used (legs). Methods Participants completed 2 stepwise incremental exercise tests to determine the relationship between power and : 1) cycling legs only, and; 2) cycling arms only. Simulation of 2 high intensity aerobic training sessions was achieved using a constant power endurance test to intolerance. In random order, participants cycled at the same aerobic demand: 1) with legs only (L + 0) at 80% of and; 2) with legs and arms (L+A) simultaneously at leg power 60% and arm power to make up for the 20% difference. Results 10 healthy volunteers (mean±SD): age 33±12; BMI 24.2±2.8 kg/m2; 112±25 %predicted) participated. The tolerance of L + 0 (mean±SE) was 6.52±0.53 min whereas the tolerance of L+A was 21.6±1.9 min and greater than L + 0 (difference 95% CI = 15.1 11.0 to 19.1 min (see Figure). The volume of aerobic work increased (32.6 22.9 to 42.2 LO2) in L+A (44.6±5.6 L) compared to L + 0 (12.1±2.0 L). Conclusions The central training stimulus was increased by distributing training among leg and arm muscle groups. Conceivably concurrent aerobic training with separate exposure to both a central stimulus (shown here) and peripheral stimulus (partitioned) will benefit people with chronic respiratory disease whose training exposure and adaptation would otherwise be limited by exercise intolerance. This abstract is funded by: supported by National Sanitarium Association Chair in Respiratory Rehabilitation Research at West Park Health Care Centre (UHN)
Dolmage et al. (Fri,) studied this question.