Percorrer por autor "Watanabe, Yasunori"
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- Assisted towing does not affect arm stroke coordination in front-crawl swimmingPublication . Moriyama, Shin-Ichiro; Watanabe, Yasunori; Toyoda, Yugo; Hamamichi, Takeru; Morais, J.E.; Neiva, Henrique P.; Forte, Pedro; Marinho, D.A.This study clarified changes in arm stroke coordination during assisted swimming. Fourteen male collegiate swimmers swam with and without an assist at a maximum effort.
- Effect of additional buoyancy swimsuits on performance of competitive swimmersPublication . Moriyama, Shin-Ichiro; Watanabe, Yasunori; Kurono, Tsubasa; Morais, J.E.; Marinho, D.A.; Wakayoshi, KohjiWhen in water, the Centers of Buoyancy (CoB) and Mass (CoM) of the human body are positioned cranially and caudally, respectively. With increasing distance between these centers, the sinking torque of the lower limbs increases, with a subsequent decrease in swimming performance due to increased drag. Objective: To clarify the effect of additional buoyancy swimsuits on swimming performance. Methods: The subjects were eight competitive male swimmers of mean ±SD age 21±2 years. Swimming performance was compared between Conventional (CS) and Additional Buoyancy Swimsuits (ABS). CoM and CoB were identified on land and in water, respectively, with the swimmers maintaining a horizontal posture. CoM was measured by the reaction board method. CoB was calculated as the force exerted in the vertical direction accompanied by changes in inspiratory volume. Swimming velocity and Blood Lactate (BL) concentration value during 200 m front crawl in trials at four different speeds (curve test) were recorded as swimming performance. Results: No significant difference in inspiratory volume was observed between CS and ABS (small effect size, d=0.28). The distance between CoM and CoB was significantly shorter for CS than ABS (p < 0.001; large effect size, d=1.08). Both swimming velocity at BL of 4 mmol·L-1 and maximal effort were significantly faster for ABS (p < 0.042; 0.008), with large effect size (d=0.91; 0.98). However, there was no significant difference in maximal BL between CS and ABS (small effect size, d=0.37).
- The impact of assisted swimming on front crawl performancePublication . Moriyama, Shin-Ichiro; Watanabe, Yasunori; Masuda, Kosuke; Toyoda, Yugo; Morais, J.E.; Forte, Pedro; Neiva, Henrique P.; Marinho, D.A.In the present study, we aimed to clarify the impact of the Assisted swim (A-swim; towing from propulsion direction) on front crawl performance at maximum and sub-maximum effort levels. Methods: Fourteen male collegiate swimmers (age, 21.0 ± 2.0 years; height, 1.73 ± 0.05 m; weight, 67.1 ± 7.1 kg) participated. Participants swam 25-m front crawl at maximal (Max) and submaximal intensity (Submax (80% of the max stroke rate (SR))) with and without an assist (assisted swimming with a towing device and normal swim (N-swim) without the device) for a total of four lengths. In addition to swim velocity (V), SR, and stroke length (SL), one stroke cycle was broken down into four phases—glide, pull, push, and recovery—and analyzed the duration of each phase. Results: A significant interaction of level of efforts and presence/absence of towing was confirmed in V, SR, and SL. V and SL showed a significant increase in A-swim compared to N-swim at both Max and Submax. SR was significantly higher in A-swim than in N-swim only at Max. Each phase of stroke showed a significant difference in recovery at Submax and push at Max. Conclusions: Despite considering the impact of propulsion from towing, A-swim increased SR, in addition to the V and SL, of swimmers compared with N-swim.