Mid Sweden University

Aim of this work was to examine the effects of decoupled two-legged cycling on (1) submaximal and maximal oxygen uptake, (2) power output at 4 mmol L^-1 blood lactate concentration, (3) mean and peak power output during high intensity cycling (30 s sprint) and (4) isometric and dynamic force production of the knee extensor and flexor muscles. 18 highly trained male competitive male cyclists and triathletes (age 24 ± 3 years; body height 179 ± 11 cm; body mass 78 ± 8 kg; peak oxygen uptake 5,070 ± 680 mL min^-1) were equally randomized to exercise on a stationary cycle equipped either with decoupled or with traditional crank system. The intervention involved 1 h training sessions, 5 times per week for 6 weeks at a heart rate corresponding to 70% of VO_2peak. VO₂ at 100, 140, 180, 220 and 260 and power output at 4 mmol L^-1 blood lactate were determined during an incremental test. VO_2peak was recorded during a ramp protocol. Mean and peak power output were assessed during a 30 s cycle sprint. The maximal voluntary isometric strength of the quadriceps and biceps femoris muscles was obtained using a training machine equipped with a force sensor. No differences were observed between the groups for changes in any variable (P = 0.15-0.90; effect size = 0.00-0.30). Our results demonstrate that a 6 week (30 sessions) training block using decoupled crank systems does not result in changes in any physiological or performance variables in highly trained competitive cyclists.