Superior performance improvements in elite cyclists following short-interval vs effort-matched long-interval training.

The purpose of this study was to compare the effects of 3 weeks with three weekly sessions (ie, nine sessions in total) of short intervals (SI; n = 9; 3 series with 13 × 30-second work intervals interspersed with 15-second recovery and 3-minutes recovery between series) against effort-matched (rate of perceived effort based) long intervals (LI; n = 9; 4 series of 5-minute work intervals with 2.5-minutes recovery between series) on performance parameters in elite cyclists ( V ˙ O 2max 73 ± 4 mL min-1  kg-1 ). There were no differences between groups in total volume and intensity distribution of training during the intervention period. SI achieved a larger (P < .05) relative improvement in peak aerobic power output than LI (3.7 ± 4.3% vs -0.3 ± 2.8%, respectively), fractional utilization of V ˙ O 2max at 4 mmol L-1 [La- ] (3.0 ± 5.8 percent points vs -3.5 ± 2.7 percent points, respectively), and larger relative increase in power output at 4 mmol L-1 [La- ] (2.0 ± 6.7% vs -2.8 ± 3.4, respectively), while there was no group difference in change of V ˙ O 2max . Improvements in performance measured as mean power output during 20-minute cycling test were greater (P < .01) in SI compared with LI (4.7 ± 4.4% vs -1.4 ± 2.2%, respectively). Mean effect size of the improvement in the above variables revealed a small to large effect of SI training vs LI training. The data thus demonstrate that the present SI protocol induces superior training adaptations compared with the present LI protocol in elite cyclists.

Adding vibration to high-intensity intervals increase time at high oxygen uptake in well-trained cyclists.

The importance of accumulated time ≥90% of maximal oxygen consumption (VO2max ) to improve performance in well-trained endurance athletes is well established. The present study compared the acute effects of adding vibrations (VIB; 40 Hz) with the work intervals during a high-intensity cycling session (HIT) with a traditional HIT session without vibration (TRAD) on time ≥90% of VO2max , time ≥90% of peak heart rate (HRpeak ), electromyography (EMG) activity, and mean power in well-trained cyclists (n = 10, VO2max =78.6 ± 7.4 mL/min/kg). The order of VIB and TRAD was randomized and consisted of 6 × 5-minutes work intervals performed with the highest possible mean power across the work intervals (2.5-minutes standardized relief periods). VIB was superior to TRAD on time ≥90% of VO2max , (10.99 ± 7.00 vs 6.95 ± 5.28 minutes, respectively), time ≥90% of HRpeak (24.61 ± 2.38 vs 19.97 ± 4.12 minutes, respectively), and averaged EMG activity in m. Vastus Lateralis during the work intervals (all P < 0.05). The EMG/power output ratio across all work intervals was higher in VIB than TRAD (P < 0.05). Mean values across work intervals showed no difference between VIB and TRAD in mean power, rate of perceived exertion, or blood lactate concentration. Thus, the present study indicated that adding vibration to the work intervals during a HIT session can acutely increase the physiological responses of the cardiovascular system and increase time ≥90% VO2max and should therefore be considered in order to optimize the exercise stimulus of well-trained cyclists.

The relationship between oxygen uptake kinetics and neuromuscular fatigue in high-intensity cycling exercise.

PURPOSE: In theory, a slow oxygen uptake ([Formula: see text]) kinetics leads to a greater accumulation of anaerobic by-products, which can, in turn, induce more neuromuscular fatigue. However, the existence of this relationship has never been tested. METHODS: After two sessions to measure peak [Formula: see text], peak power output (POpeak), and [Formula: see text] kinetics responses in the unfatigued state (τ [Formula: see text] MOD), 10 healthy young adults performed a 6-min cycling bout at 80% POpeak (INT6-min). [Formula: see text] kinetics responses were also measured during INT6-min. Neuromuscular fatigue was measured isometrically pre- and post-INT6-min (immediately post- and 15-s post-INT6-min) with an innovative cycle ergometer. RESULTS: Maximal voluntary contraction (MVC) force, high-frequency doublet amplitude, and the ratio of low- to high-frequency doublet amplitudes decreased by 34 ± 7, 43 ± 11, and 31 ± 13%, respectively (all P < 0.01). A significant Spearman's rank correlation was observed between the change in low-frequency doublet force (ΔDb10) immediately after INT6-min and both τ [Formula: see text] MOD and τ [Formula: see text] INT6-min (ρ = -0.68 and ρ = -0.67, both P < 0.05). When considering the largest responses from the two neuromuscular evaluations post-INT6-min, significant correlations were also found between τ [Formula: see text] MOD and ΔDb10 (ρ = -0.74; P < 0.05) and between τ[Formula: see text] INT6-min and both ΔDb10 and low-frequency fatigue (ρ = -0.70 and ρ = -0.66; both P < 0.05). CONCLUSION: The present results suggest that subjects with slow [Formula: see text] kinetics experience more peripheral fatigue, in particular more excitation-contraction coupling failure, likely due to a greater accumulation of protons and/or inorganic phosphates.

Short intervals induce superior training adaptations compared with long intervals in cyclists - an effort-matched approach.

The purpose of this study was to compare the effects of 10 weeks of effort-matched short intervals (SI; n = 9) or long intervals (LI; n = 7) in cyclists. The high-intensity interval sessions (HIT) were performed twice a week interspersed with low-intensity training. There were no differences between groups at pretest. There were no differences between groups in total volume of both HIT and low-intensity training. The SI group achieved a larger relative improvement in VO(2max) than the LI group (8.7% ± 5.0% vs 2.6% ± 5.2%), respectively, P ≤ 0.05). Mean effect size (ES) of the relative improvement in all measured parameters, including performance measured as mean power output during 30-s all-out, 5-min all-out, and 40-min all-out tests revealed a moderate-to-large effect of SI training vs LI training (ES range was 0.86-1.54). These results suggest that the present SI protocol induces superior training adaptations on both the high-power region and lower power region of cyclists' power profile compared with the present LI protocol.