Author(s): CONSTANTINI, K., OHAYON, E., KADOSH, S.M., MARCUS, I., VIEIRA, T.M., Institution: TEL AVIV UNIVERSITY, Country: ISRAEL, Abstract-ID: 2380

INTRODUCTION:
There is a wide spread notion among coaches and athletes that cycling at a high cadence is advantageous for athletic performance. However, scientific data indicates that - at least metabolically - the “optimal” cadence is lower. Specifically, various physiological variables (e.g., heart rate (HR), O2 uptake (VO2), blood lactate concentration (BLa-)) have been shown to be lowest (i.e., physiologically advantageous) at cadences of 50-60 rpm, while cycling on a stationary ergometer – a condition that does not reflect real life cycling. Thus, this study aimed to comprehensively examine the effects of different cadences on metabolic, ventilatory and perceptual variables while riding on a motorized treadmill.
METHODS:
Fifteen highly trained cyclists and triathletes (F=1; MeanSD: age: 246 years; height: 1.760.05 m; weight: 66.95.1 kg) completed two exercise sessions: 1) maximal graded exercise test from which maximal O2 uptake (VO2max) and power output at the first ventilatory threshold (VT1), and 2) a 30-min submaximal bout at constant power output equivalent to 110% VT1. Every 5 minutes during the submaximal effort, subjects were instructed to change gears to match the target cadence (60, 70, 80, 90, 100 or 110 rpm, in a random order). HR and metabolic variables were continuously recorded, while rating of perceived exertion (RPE; 0-10 scale) and BLa- were obtained at the end of every stage. Mixed linear models were used to assess differences in physiological variables between cadences.
RESULTS:
On Average, VO2max was 65.9+_8.3 ml/kg/min and power output at 110%VT1 was 235+_46 watts. VO2 was significantly (p<0.01) lower at 60 rpm (3127+_546 l/min), and CO2 production (VCO2) was significantly (p<0.01) lower at both 60 and 70 rpm (2862+_503 and 2878+_503 l/min, respectively), compared to 90 rpm (VO2: 3218+_546; VCO2: 2960+_503 l/min). No other variables were different between 90 rpm and lower cadences. VO2 and VCO2 were significantly (p<0.01) higher at 100 rpm (3319+_546 & 3085+_503 l/min, respectively) and 110 rpm (3410+_546 & 3226+_503 l/min, respectively) compared to 90 rpm. At 110 rpm, minute ventilation (VE; 101.0+_18.6 l/min), respiratory exchange ratio (RER; 0.95+_0.02), %carbohydrates (CHO) oxidation (81.3+_7.5%), HR (156+_16 beats/min), BLa- (2.9+_1.2 mmol) and RPE (5.3+_1.4) were significantly (p<0.01) higher than 90 rpm (VE: 88.6+_18.6 l/min; RER: 0.92+_0.02; CHO oxidation: 72.9+_7.5 %; HR: 148+_16 beats/min; BLa-: 2.0+_1.2 mmol; RPE: 3.8+_1.4).
CONCLUSION:
This study is the first to examine physiological responses at different cadences while riding on a motorized treadmill, which more closely mimics real world cycling than a stationary ergometer. Our findings indicate that while riding at cadences >100 rpm is more taxing from a physiological and perceptual standpoint than lower cadences, these responses are similar at 60-90 rpm. Thus, using high cadences should be reconsidered as lower ones might be more beneficial, especially for endurance and metabolic efficiency.