Continuous Leg Cycling Ergometry Prescribed at Identical Relative Power Output Elicits Different Physiological Responses Versus Arm Cycle Ergometry

PURPOSE: The aim of this study was to compare physiological and perceptual responses to progressive moderate intensity continuous exercise (MICE) between leg (LCE) and arm cycle ergometry (ACE). METHODS: Seventeen active men and women (age and percent body fat = 26 ± 7 yr and 18 ± 3 %) initially performed graded exercise on each modality to assess maximal oxygen uptake (VO2max) and peak power output (PPO). Using a randomized crossover design, they subsequently performed 45 min of MICE consisting of three 15 min bouts at 20, 40, and 60 % PPO on each modality. Gas exchange data (VO2, VCO2, VE, and respiratory exchange ratio (RER), heart rate (HR), blood lactate concentration (BLa), affective valence, and rating of perceived exertion (RPE) were acquired during each bout. RESULTS: Compared to ACE, LCE revealed significantly higher (p \u3c 0.05) peak (94 ± 6 vs. 88 ± 9 %HRmax, d = 0.81) and mean HR (73 ± 6 vs. 66 ± 6 %HRmax, d = 1.20) and VO2 (54 ± 5 vs. 50 ± 7 %VO2max, d = 0.68). Time spent above 70 (22 ± 7 vs. 15 ± 8 min, d = 1.03) and 80 %HRmax (15 ± 6 vs. 9 ± 6 min, d = 1.04) was significantly greater with LCE versus ACE. LCE revealed significantly higher BLa versus ACE (5.5 ± 2.0 vs. 4.7 ± 1.5 mM, d = 0.48). CONCLUSIONS: These results exhibit that progressive leg cycling at identical intensities elicits a greater cardiometabolic stimulus than arm ergometry. Moreover, leg cycling leads to greater duration spent at intensities between 70 – 89 %VO2max which may have application to selecting specific exercise modes when prescribing MICE to increase cardiorespiratory fitness. Lastly, use of %PPO led to participants being classified in different intensity domains which merits prescribing MICE according to various threshold measures rather than relative intensities acquired from incremental exercise

Identifying Maximal Fat Oxidation during Arm Ergometry

Metabolic responses have been extensively studied in response to various exercise modalities, such as treadmill running and cycling. Achten et al. (2002) demonstrated that graded exercise testing in trained cyclists using 3 minute (min) stages led to similar estimates of fat oxidation (FOx) and maximal fat oxidation (MFO) as 5 min stages. However, minimal research has studied FOx responses during exercises using arm cycle ergometry (ACE). PURPOSE: To compare FOx responses during progressive ACE using 3 and 5 min stages. METHODS: Participants consisted of 11 healthy, non-obese men and women (age = 24±9 yr, %BF = 23±5%, VO2peak and PPO = 23.5±5.7 ml/kg/min and 103.2±40.4 W) who are physically active (PA = 5±2 h/wk) but unfamiliar with ACE. Participants initially underwent graded exercise testing to determine peak oxygen uptake (VO2peak) and peak power output (PPO) on the ACE. Utilizing a randomized crossover design, on two separate days, following a 12 h fast, participants performed progressive exercise on the ACE with gradually increasing intensities every 3 or 5 min, starting at 15%PPO and PO increasing by 10% per stage. Gas exchange data, heart rate (HR), and blood lactate concentration (BLa) were obtained throughout exercise. RESULTS: Paired t-test showed no significant differences in MFO between 3 and 5 min stages (0.16±0.07 vs 0.13±0.07 g/min, p=0.07), and there was a strong, positive correlation between these values (r=0.82, p =0.002). There were no significant differences between protocols in BLa at MFO (1.94 ±1.0 vs. 1.95±0.8 mM, p= 0.93), MFO expressed as percent of peak HR (%HRpeak) (59±9 vs. 58±11 %HRpeak, p= 0.80), % VO2peak (38±8 vs. 42±15% VO2peak, p= 0.24) or power output (PO) at MFO (26±12 vs. 24±10 %PPO, p= 0.17). However, RER at MFO was significantly different between 3 and 5 min stages (0.83±0.05 vs. 0.86±0.03, p= 0.04). Results showed no significant duration X time interaction for BLa (p= 0.25), FOx (p= 0.44), carbohydrate oxidation (CHOOx) (p= 0.057), RER (p= 0.61), or blood glucose (p= 0.24) between stage durations. CONCLUSION: As no significant differences in FOx were revealed between stage durations, we recommend 3 min stages to identify metabolic responses during progressive ACE. However, more study is merited to elucidate the individual variability in the FOx response to exercise

Comparing Physiological Responses During Rowing High Intensity Interval Training (HIIT) versus High Intensity Functional Training (HIFT)

High intensity interval training (HIIT) improves cardiorespiratory fitness, glycemic control, and body composition, yet the majority of studies used cycling which employs a smaller muscle mass. Less data have examined the acute response to whole-body HIIT. PURPOSE: To compare physiological responses between HIIT rowing and high intensity functional training (HIFT). METHODS: Healthy, non-obese men and women (N=18, age=25±8 yr) who are physically active (PA=7±2hr, VO2max=39±8mL/kg/min) underwent graded exercise testing to determine VO₂max and peak power output (PPO) on the rowing ergometer. On two separate days, subjects performed a time-matched bout of HIFT or HIIT rowing. HIIFT required 6 ‘all-out’ sets of 10 push-ups, 10 jump squats, 20 mountain climbers, and 20 body-weight squats separated by 75 s recovery. HIIT rowing consisted of six 1min bouts at 85% PPO with 75 s of recovery. Gas exchange data, heart rate (HR), affective valence, and RPE were obtained during exercise. Blood lactate concentration (BLa) was measured at rest, bout 3, and 5, 10, and 15 min post-exercise. RESULTS: There were significant differences (p2 was higher (p=0.03) with HIIT rowing versus HIFT (1.88 ± 0.51 vs. 1.67 ± 0.35 L/min) as was total O2 (31±8 vs. 28±6L). GroupXtime interactions (pE, and RPE occurred, with higher values demonstrated to HIFT. CONCLUSION: HIFT elicited a higher peak HR, BLa, and RER, suggesting a higher peak cardiovascular stimulus and greater activation of glycolysis, likely due to greater recruitment of fast twitch fibers. Yet, HIIT rowing elicited higher energy expenditure and mean VO2 versus HIFT. The eccentric nature of HIFT may explain the blunted VO2 response, although more studies are needed to verify this result