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This study was aimed to: (1) investigate the effects of physiological functions of sprint interval training (SIT) on the aerobic capacity of elite badminton players; and (2) explore the potential mechanisms of oxygen uptake, transport and recovery within the process. Thirty-two elite badminton players volunteered to participate and were randomly divided into experimental (Male-SIT and Female-SIT group) and control groups (Male-CON and Female-CON) within each gender. During a total of eight weeks, SIT group performed three times of SIT training per week, including two power bike trainings and one multi-ball training, while the CON group undertook two Fartlek runs and one regular multi-ball training. The distance of YO-YO IR2 test (which evaluates player’s ability to recover between high intensity intermittent exercises) for Male-SIT and Female-SIT groups increased from 1083.0 ± 205.8 m to 1217.5 ± 190.5 m, and from 725 ± 132.9 m to 840 ± 126.5 m (p < 0.05), respectively, which were significantly higher than both CON groups (p < 0.05). For the Male-SIT group, the ventilatory anaerobic threshold and ventilatory anaerobic threshold in percentage of VO2max significantly increased from 3088.4 ± 450.9 mL/min to 3665.3 ± 263.5 mL/min (p < 0.05),and from 74 ± 10% to 85 ± 3% (p < 0.05) after the intervention, and the increases were significantly higher than the Male-CON group (p < 0.05); for the Female-SIT group, the ventilatory anaerobic threshold and ventilatory anaerobic threshold in percentage of VO2max were significantly elevated from 1940.1 ± 112.8 mL/min to 2176.9 ± 78.6 mL/min, and from 75 ± 4% to 82 ± 4% (p < 0.05) after the intervention, which also were significantly higher than those of the Female-CON group (p < 0.05). Finally, the lactate clearance rate was raised from 13 ± 3% to 21 ± 4% (p < 0.05) and from 21 ± 5% to 27 ± 4% for both Male-SIT and Female-SIT groups when compared to the pre-test, and this increase was significantly higher than the control groups (p < 0.05). As a training method, SIT could substantially improve maximum aerobic capacity and aerobic recovery ability by improving the oxygen uptake and delivery, thus enhancing their rapid repeated sprinting ability.

The study aimed to investigate the post-activation performance enhancement (PAPE) of flywheel training (FT) on lower limb explosive power performance. Using a randomized crossover design, 20 trained men (age = 21.5 ± 1.4 years; training experience 5.5 ± 1.2 years) completed seven main conditions after three familiarization sessions. The first three conditions tested the PAPE of the FT on the counter movement jump (CMJ) under three different inertial loads (0.041 kg·m2 as L; 0.057 kg·m2 as ML; and 0.122 kg·m2 as P), whereas the following four conditions tested the PAPE of FT on the 30 m sprint, which consisted of three inertial loads (L, ML, and P) and a control condition. Participants were required to perform the CMJ or 30 m sprint at baseline (Tb) and immediately (T0), 4 min (T4), 8 min (T8), 12 min (T12), and 16 min (T16) after exercise, respectively. The results of the CMJ conditions showed that PAPE peaked at T4 (p &lt; 0.01) and almost subsided at T12 (p &gt; 0.05) in ML and P conditions. Meanwhile, PAPE appeared earlier in the P condition, and the effect was more significant (P:ES = 1.09; ML:ES = 0.79). 30 m sprint results showed significant improvement only in the ML condition. The PAPE peaked at T4 (p &lt; 0.05, ES = −0.47) and almost subsided at T8 (p &gt; 0.05). It was mainly due to the significant enhancement of the 10–30 m segmental timing performance at T4 (p &lt; 0.05, ES = −0.49). This study indicates that the size of the inertial load could influence the magnitude of the PAPE produced by the explosive force of the lower limb. The PAPE of the vertical explosive force increased with increasing inertial load, but the PAPE of the horizontal explosive force did not appear at the maximum inertial load. The most effective elicitation of the PAPE was at 4–8 min after the FT.

No abstract

The 1,3-dipolar cycloaddition of an azomethine ylide generated by a decarboxylative route from sarcosine and acenaphthenequinone to 7-arylmethylidene-3-aryl-3,4-dihydro-2H-thiazolo[3,2-a][1,3,5]triazin-6(7H)-ones afforded novel dispiro[acenaphthylene-1,2'-pyrrolidine]-3',7''-[1,3]thiazolo[3,2-a][1,3,5]triazines in moderate yields. The structures of the products were determined and characterized thoroughly by NMR, MS, IR, elemental analysis and X-ray crystallographic analysis. The results of experiment indicated that this 1,3-dipolar cycloaddition proceeded with high stereoselectivity and regioselectivity.