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Hypoxic Exposure at Rest or During Light to Moderate-Intensity Exercise Improved Blood Pressure and Heart Rate Variability in Cardiovascular Risk Individuals, JEPonline 2023;26(3):28-44. This study evaluated the effects of 6 weeks of intermittent hypoxic at rest or plus exercise and long-lasting effects on blood pressure and heart rate variability (HRV) in cardiovascular risk individuals. Thirty combinations of several CVD risks participants: hypertension, hyperlipidemia, and obesity were randomly allocated into 3 groups: (a) the Control Group (CON, n = 11) received no intervention; (b) the intermittent hypoxic exposure during rest (IHR, n = 9), and the intermittent hypoxic training (IHT, n = 10) combined with walking on a motorized treadmill at a light to moderate-intensity. Both IHR and IHT performed 8 sessions of 3 minutes of hypoxic breathing alternated with 3 minutes of normoxic breathing for 6 weeks. All participants blood pressure and HRV were measured at baseline, at week 6 (POST1), and at week 10 (POST2). The IHR and IHT Groups showed significantly lower SBP (P < 0.05) compared to the CON Group, but not DBP and MAP after the IH training program. Compared to CON, the low-frequency band (VLF) and the low-frequency band and the high-frequency band (LF/HF ratio) showed a significant decrease only in IHT (P < 0.05) at POST1 and VLF remained significantly decreased at POST2. VLF in the IHT Group remained significantly lower than in the IHR Group at POST2. After the IH training program, IHT revealed a significant increase in HF (P < 0.05) compared to the CON Group. HF (n.u.) was a significantly stronger negative correlation with changes in SBP (P < 0.05). The IHT Group showed more effectiveness than the IHR Group. The study suggested this IH training program improved SBP and HRV at POST1. An increase in parasympathetic activity may have played an important role in the SBP reduction seen in this study. [ABSTRACT FROM AUTHOR]

Strength training in hypoxia has been shown to enhance hypertrophy and function of skeletal muscle, however, the effects of plyometric training in hypoxia is relatively unknown. Therefore, this study aimed to examine the effects of plyometric training in hypoxia compared to normoxia on body composition, sprint and jump parameters. Twenty-three male physical education students (20.4±2.0 years, mean±SD) participated in the study and were divided into a plyometric training in hypoxia (PTH, n=8), plyometric training in normoxia (PTN, n=7) or control group (C, n=8). The PTH group trained in normobaric hypoxia (approximately 3536 m) 3 days/week for 8 weeks, while the PTN trained in normoxia. PTH induced significant improvements from baseline to post-testing in countermovement-jump (37.8±6.7 cm, 43.4±5.0 cm, p<0.05), squat-jump (35.4±6.2 cm, 41.1±5.7 cm, p<0.05), drop-jump height (32.8±6 cm, 38.1±6 cm, p<0.05) and 20-m sprint performance (3257.1±109.5 ms, 3145.8±83.6 ms, p<0.05); whereas PTN produced significant improvement only in countermovement-jump (37.3±4.8 cm, 40.5±4.5 cm, p<0.05) and 20-m sprint performance (3209. 3±76.1 ms, 3126.6±100.4 ms, p<0.05). Plyometric training under hypoxic conditions induces greater improvement in some jump measures (drop-jump and squat-jump) compared to similar training in normoxia. [ABSTRACT FROM AUTHOR]

Busbridge, AR, Hamlin, MJ, Jowsey, JA, Vanner, MH, and Olsen, PD. Running demands of provincial women's rugby union matches in New Zealand. J Strength Cond Res 36(4): 1059-1063, 2022-There has been rapid growth in participation in women's rugby but there is minimal research on the sport. The aim of this study was to increase our knowledge of the running demands of high-level female players in the New Zealand Provincial Rugby Competition. Players (n = 20) wore 10-Hz Global Positioning System units during 7 matches to measure total distance covered, all running distance (>=6.4 km[middle dot]h-1), high-intensity (HI) running (>=16.1 km[middle dot]h-1), meters per minute (m[middle dot]min-1), and maximum speed (km[middle dot]h-1). Mean +/- SD were calculated for forwards and backs. Forwards and backs covered a similar total distance (5,616 +/- 809 m and 5,852 +/- 1,022 m, respectively) and running distance (3,181 +/- 583 m and 3,095 +/- 805 m, respectively). However, when separated into specific playing positions, the half back recorded significantly higher running distances (4,292 +/- 171 m), greater HI running distances (1,003 +/- 58 m), and more distance overall (6,812 +/- 277 m) than other positions (p <= 0.05). By contrast, outside backs did less running (2,456 +/- 114 m) than other positions (p <= 0.05), and had the lowest distance for HI running (528 +/- 39 m) in the backs. Running demands were similar for forwards and backs; however, within positions there was considerable variation, and the lower running measurements for outside backs maybe unique to women's rugby. Due to these findings and possible different tactical approaches, the development of training and speed zone bands specific to female players is advised because male research findings may lack transferability to women's rugby. /=> [ABSTRACT FROM AUTHOR]

Purpose: Lower barometric air pressure at altitude can affect competitive performance of athletes in some sports. Reported here are the effects of various altitudes on elite track-and-field athletes' performance. Methods: Lifetime track-and-field performances of athletes placed in the top 16 in at least 1 major international competition between 2000 and 2009 were downloaded from the database at tilastopaja.org. There were 132,104 performances of 1889 athletes at 794 venues. Performances were log-transformed and analyzed using a mixed linear model with fixed effects for 6 levels of altitude and random quadratic effects to adjust for athlete age. Results: Men's and women's sprint events (100-400 m) showed marginal improvements of ~0.2% at altitudes of 500-999 m, and above 1500 m all but the 100- and 110-m hurdles showed substantial improvements of 0.3-0.7%. Some middle- and long-distance events (800-10,000 m) showed marginal impairments at altitudes above 150 m, but above 1000 m the impairments increased dramatically to ~2-4% for events >800 m. There was no consistent trend in the effects of altitude on field events up to 1000 m; above 1000 m, hammer throw showed a marginal improvement of ~1% and discus was impaired by 1-2%. Above 1500 m, triple jump and long jump showed marginal improvements of ~1%. Conclusions: In middle-and long-distance runners, altitudes as low as 150 to 299 m can impair performance. Higher altitudes (>1000 m) are generally required before decreases in discus performance or enhancements in sprinting, triple and long jump, or hammer throw are seen. [ABSTRACT FROM AUTHOR]

Purpose: To compare whole-body vibration (WBV) with traditional recovery protocols after a high-intensity training bout. Methods: In a randomized crossover study, 16 athletes performed 6 × 30-s Wingate sprints before completing either an active recovery (10 min of cycling and stretching) or WBV for 10 min in a series of exercises on a vibration platform. Muscle hemodynamics (assessed via near-infrared spectroscopy) were measured before and during exercise and into the 10-min recovery period. Blood lactate concentration, vertical jump, quadriceps strength, flexibility, rating of perceived exertion (RPE), muscle soreness, and performance during a single 30-s Wingate test were assessed at baseline and 30 and 60 min postexercise. A subset of participants (n = 6) completed a 3rd identical trial (1 wk later) using a passive 10-min recovery period (sitting). Results: There were no clear effects between the recovery protocols for blood lactate concentration, quadriceps strength, jump height, flexibility, RPE, muscle soreness, or single Wingate performance across all measured recovery time points. However, the WBV recovery protocol substantially increased the tissue-oxygenation index compared with the active (11.2% ± 2.4% [mean ± 95% CI], effect size [ES] = 3.1, and –7.3% ± 4.1%, ES = –2.1 for the 10 min postexercise and postrecovery, respectively) and passive recovery conditions (4.1% ± 2.2%, ES = 1.3, 10 min postexercise only). Conclusion: Although WBV during recovery increased muscle oxygenation, it had little effect in improving subsequent performance compared with a normal active recovery. [ABSTRACT FROM AUTHOR]

The benefit of resistance training under hypoxic conditions continues to draw considerable debate. This research explored the optimal degree of hypoxia combined with low-load resistance training which mimics the high-load traditional resistance training under normoxic condition. Thirty-seven male team sport athletes were divided into 3 resistance training groups; 1) normoxic high-load (NRT), 2) hypoxic low-load (HRT13.6, FiO2 = 13.6%), and 3) hypoxic low-load (HRT15.8, FiO2 = 15.8%). Training included 3 sets of 15 reps at either 80%1RM (high-load) or 50%1RM (low-load), 3 days per week. Muscle thickness (via ultrasonography) along with strength and muscular endurance were measured pre (1-2 days prior) and post (2-3 days post) a 5-week training period. Rectus femoris muscle thickness significantly increased in all groups, but was greater in the HRT13.6 group (18.3 ± 7.6%, mean ± SD) compared to the NRT group (9.1 ± 7.3%, p = 0.02). Similarly, muscle strength increased in all groups, but the HRT13.6 group showed a significantly larger improvement in isometric knee extension MVC (33.5 ± 12.7%) compared to the NRT group (19.8 ± 6.5%, p = 0.04). Finally, rectus femoris fat layer thickness was significantly reduced after training, particularly in the HRT13.6 group (-55.8 ± 5.5%) compared to NRT (-32.8 ± 9.6%, p = 0.01) and HRT15.8 groups (-38.2 ± 12.5%, p = 0.01). Low-load resistance training particularly in 13.6% oxygen, produced more muscle thickness, fat loss, and bigger strength gains compared to traditional high-load resistance training. This training strategy may be a useful alternative to traditional high-load resistance training. [ABSTRACT FROM AUTHOR]