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Information regarding the effects of stretching intensity on the joint torque-angle response is scarce. The present study examined the effects of three static stretching protocols with different intensities and durations on the passive knee extension torque-angle response of seventeen male participants (age ± SD: 23.9 ± 3.6 years, height: 177.0 ± 7.2 cm, BMI: 22.47 ± 1.95 kg · m(2)). The stretching intensity was determined according to the maximal tolerable torque of the first repetition: fifty per cent (P50), seventy-five per cent (P75) and the maximum intensity without pain (P100). Five repetitions were performed for each protocol. The stretch duration of each repetition was 90, 135 and 180 s for P100, P75 and P50, respectively. The rest period between repetitions was 30 s. Passive torque at a given angle, angle, stress relaxation, area under the curve, surface electromyography activity and visual analogue scale score were compared. The significant (P < 0.05) results found were as follows: (i) the P50 and P75 did not increase the angle and passive peak torque outcomes, despite more time under stretch; (ii) only the P100 increased the angle and passive peak torque outcomes; (iii) the perception of stretching intensity mainly changed depending on knee angle changes, and not passive torque; (iv) the P50 induced a higher passive torque decrease; (v) when protocols were compared for the same time under stretch, the torque decrease was similar; (vi) the change in torque-angle curve shape was different depending on the stretching protocol. In conclusion, higher stretch duration seems to be a crucial factor for passive torque decrease and higher stretch intensity for maximum angle increase.

We explored whether interval walking with blood flow restriction (BFR) increases net metabolic cost of locomotion in healthy young men at their optimal walking speed. We also determined whether decreased walking economy resulting from BFR might be accompanied by an increase in ventilation relative to VO2 and VCO2 . Finally, we examined possible relationships between the changes in ratings of perceived exertion (RPE) and those obtained in minute ventilation (VE ) during walking with BFR. Eighteen healthy men (age: 22·5 ± 3·4 years) performed graded treadmill exercise to assess VO2max . In a randomized fashion, participants also performed five bouts of 3-min treadmill exercise with and without BFR at their optimal walking speed. Walking with BFR elicited an overall increase in net VO2 (10·4%) compared with that seen in the non-BFR condition (P0·05). The participants also demonstrated greater VE and VE /VO2 values while walking with BFR (P0·05). Conversely, VE /VCO2 was similar between conditions at each walking bout. We found no significant correlation between the changes in VE and RPE induced by walking with BFR (r = 0·38, P0·05). Our results indicate that (i) BFR decreases net walking economy in healthy young men, even at their optimal walking speed; (ii) heightened ventilatory drive may explain a small proportion of BFR effects on walking economy; and (iii) the ventilatory responses to BFR walking may be largely independent of changes in perceived exertion and are likely matched to the flux of CO2 between muscles and respiratory centres.