The Acute Effects of Normobaric Hypoxia on Strength, Muscular Endurance and Cognitive Function: Influence of Dose and Sex.

The aim of this study was to examine the acute effects of different levels of hypoxia on maximal strength, muscular endurance, and cognitive function in males and females. In total, 13 males (mean ± SD: age, 23.6 ± 2.8 years; height, 176.6 ± 3.9 cm; body mass, 76.6 ± 2.1 kg) and 13 females (mean ± SD: age, 22.8 ± 1.4 years; height, 166.4 ± 1.9 cm; body mass, 61.6 ± 3.4 kg) volunteered for a randomized, double-blind, crossover study. Participants completed a one repetition strength and muscular endurance test (60% of one repetition maximum to failure) for squat and bench press following four conditions; (i) normoxia (900 m altitude; FiO2: 21%); (ii) low dose hypoxia (2000 m altitude; FiO2: 16%); (iii) moderate dose hypoxia (3000 m altitude; FiO2: 14%); and (iv) high dose hypoxia (4000 m altitude; FiO2: 12%). Heart rate, blood lactate, rating of perceived exertion, and cognitive function was also determined during each condition. The one repetition maximum squat (p = 0.33) and bench press (p = 0.68) did not differ between conditions or sexes. Furthermore, squat endurance did not differ between conditions (p = 0.34). There was a significant decrease in bench press endurance following moderate (p = 0.02; p = 0.04) and high (p = 0.01; p = 0.01) doses of hypoxia in both males and females compared to normoxia and low dose hypoxia, respectively. Cognitive function, ratings of perceived exertion, and lactate were also significantly different in high and moderate dose hypoxia conditions compared to normoxia (p < 0.05). Heart rate was not different between the conditions (p = 0.30). In conclusion, high and moderate doses of acute normobaric hypoxia decrease upper body muscular endurance and cognitive performance regardless of sex; however, lower body muscular endurance and maximal strength are not altered.

Effect of Exercise and Quercetin in Rats with Metabolic Syndrome Induced with Fructose.

Background: Metabolic syndrome (MetS), one of the most researched topics in recent years, is a metabolic disorder that presents with increased inactivity and has increasing prevalence in the developing world where many ready-made foods are consumed. This research aimed to investigate the protective effect of exercise and quercetin administration in a rat model of MetS induced by fructose. Methods: Forty-two male rats were divided into seven groups (n = 6): control (C), fructose (F), exercise (E), quercetin (Q), fructose+exercise (F+E), fructose+quercetin (F+Q), and fructose+quercetin+exercise (F+Q+E). Fructose was given as 20% solution in drinking water, and quercetin (15 mg/kg/day) was administered by oral gavage. Treadmill running exercises were applied 30 min a day for 5 days a week. After the experiments, biochemical assays, Lee index, and body fat mass analyses were measured. Result: Fructose administration caused a statistically significant increase in systolic blood pressures (SBP), triglycerides (TG), VLDL-cholesterol, glucose, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) compared with the control group, and the MetS model was successfully demonstrated (P < 0.05). It was determined that SBP, serum TG, serum insulin, HOMA-IR, and Lee indexes, and body fat mass, were decreased in the F + E group (P < 0.05). In addition, it was found that the MetS-related parameters improved, except lipid profile in the F + Q group (P < 0.05). Conclusion: These results show that high fructose consumption leads to elevated SBP, TG, cholesterol, body fat mass, glucose, insulin, and HOMA-IR levels, and aerobic exercise training treatment has beneficial effects on these biochemical parameters in rats. Although quercetin has positive effects on SBP and insulin levels, it was observed to cause a significant increase especially in TG and body fat mass. Therefore, more detailed dose studies and pathways of quercetin are needed to elucidate its mechanism of action in body fat mass.

Impacts of different intensities of exercise on inflammation and hypoxia markers in low altitude.

BACKGROUND: This study aims to determine and compare the effects of exercise modalities with different intensities on the secretion of key inflammation and hypoxia markers in amateur athletes. METHODS: Twenty-three athletes with a mean age of 20.1 years, living at low altitude (1850 m) participated in this study. The participants' maximal oxygen consumption values (VO2 max) were determined with an incremental cycle exercise test as 54.15 ± 6.14 mL kg min-1. Athletes performed four protocols: at rest, 50% VO2 max, 75% VO2 max and 100% VO2 max (until exhaustion) with one-week intervals. 50% VO2 max, 75% VO2 max sessions were performed continuously for 30 min on a bicycle ergometer and 100% VO2 max session was performed by cycling until exhaustion. Blood samples were obtained at rest and immediately after each exercise session. Serum tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP), interleukin-10 (IL-10), and hypoxia inducible factor-1 alpha (HIF-1α) levels were measured. RESULTS: There were significant differences in serum TNF-α levels in 75% VO2 max and 100% VO2 max sessions (489.03 ± 368.37 and 472.70 ± 365.21 ng/L, respectively) compared to rest conditions (331.65 ± 293.52 ng/L). Serum CRP levels of 50% VO2 max and 75% VO2 max sessions (1.19 ± 0.50; 1.07 ± 0.52 mg/L) were significantly higher than the rest condition (0.74 ± 0.35 mg/L). There were significant differences in serum IL-10 levels of rest condition and 50% VO2 max; 50% VO2 max, and 100% VO2 max sessions (328.09 ± 128.87; 446.36 ± 142.84; 347.44 ± 135.69; 324.88 ± 168.06 pg/mL). Serum HIF-1α levels were significantly higher in 75% VO2 max session compared to rest (1.26 ± 0.16; 1.08 ± 0.19 ng/mL) (P < 0.05 for all comparisons). CONCLUSIONS: Both inflammatory and anti-inflammatory pathway is induced on different exercise intensities. Exercise protocols performed until exhaustion may lead to activation of inflammatory pathways and hypoxia-induced damage.

High Dose of Caffeine Mouth Rinse Increases Resistance Training Performance in Men.

Caffeine mouth rinsing (CMR) has been shown to enhance exercise performance. However, no studies have analyzed the effects of different dosages of CMR on muscular performance. Therefore, the purpose of this study was to examine the effects of different dosages of CMR on strength (bench press 1 repetition maximum (1-RM)) and muscular endurance (60% of 1-RM repetitions to failure) in resistance-trained males. Fourteen resistance-trained males (age: 23 ± 2 years, height: 179 ± 3 cm, body mass: 83 ± 4 kg, BMI: 17 ± 2 kg/m2) completed four conditions in random order. The four conditions consisted of a mouth rinse with 25 mL solutions containing either 1% (250 mg) of CMR (low dose of CMR: LCMR), 2% (500 mg) of CMR (moderate dose of CMR: MCMR), 3% (750 mg) of CMR (high dose of CMR: HCMR) and sweetened water (placebo: PLA) for 5 s prior to a bench press strength and muscular endurance test. Maximal strength, muscular endurance, heart rate (HR) and ratings of perceived exertion (RPE) were recorded for each condition. There were no significant differences in strength (p = 0.30) and HR (p = 0.83) between conditions. HCMR significantly increased muscular endurance performance (p = 0.01) and decreased RPE values (p = 0.01). In conclusion, CMR did not affect bench press 1-RM strength performance, but muscular endurance responses to CMR seems to be dose-dependent.

The Effects of 15 or 30 s SIT in Normobaric Hypoxia on Aerobic, Anaerobic Performance and Critical Power.

Sprint interval training (SIT) is a concept that has been shown to enhance aerobic-anaerobic training adaptations and induce larger effects in hypoxia. The purpose of this study was to examine the effects of 4 weeks of SIT with 15 or 30 s in hypoxia on aerobic, anaerobic performance and critical power (CP). A total of 32 male team players were divided into four groups: SIT with 15 s at FiO2: 0.209 (15 N); FiO2: 0.135 (15 H); SIT with 30 s at FiO2: 0.209 (30 N); and FiO2: 0.135 (30 H). VO2max did not significantly increase, however time-to-exhaustion (TTE) was found to be significantly longer in the post test compared to pre test (p = 0.001) with no difference between groups (p = 0.86). Mean power (MPw.kg) after repeated wingate tests was significantly higher compared to pre training in all groups (p = 0.001) with no difference between groups (p = 0.66). Similarly, CP was increased in all groups with 4 weeks of SIT (p = 0.001) with no difference between groups (p = 0.82). This study showed that 4 weeks of SIT with 15 and 30 s sprint bouts in normoxia or hypoxia did not increased VO2max in trained athletes. However, anerobic performance and CP can be increased with 4 weeks of SIT both in normoxia or hypoxia with 15 or 30 s of sprint durations.

The acute effect of different stretching methods on sprint performance in taekwondo practitioners.

BACKGROUND: The purpose of this study was to compare the acute effects of different stretching types on sprint performance in taekwondo practitioners. METHODS: Twelve male taekwondo practitioners performed stretching exercises using different types (ballistic, proprioceptive neuromuscular facilitation [PNF], static stretching) in a random order at three-day intervals; there was also a control condition involving no stretching exercises. The subjects performed 2 maximal 20-m sprints (with 10-m split times also recorded) with a recovery period of 1 minute immediately post stretching and at 5, 10, 15 and 20 minutes after stretching. They also performed these sprints before doing the stretching exercises. RESULTS: The study results showed that sprint times significantly increased after static stretching (10-m pre =1.84±0.07 s, 10-m post =1.89±0.08 s; 20-m pre =3.33±0.19 s, 20-m post= 3.38±0.2 s), PNF stretching (10-m pre =1.84±0.07 s, 10-m post =1.89±0.08 s; 20-m pre =3.33±0.19 s, 20-m post =3.38±0.20 s) and ballistic stretching (pre =1.84±0.08 s, post =1.86±0.07 s; 20-m pre =3.33±0.20 s, 20-m post =3.35±0.21 s) (P<0.05). In the static stretching condition, 10-m and 20-m sprint performance had fully returned to normal at 15 minutes after stretching. In the PNF stretching condition, 20-m sprint performance returned to normal levels at 15 minutes after stretching, while 10-m performance took 20 minutes to recover fully. In the ballistic stretching method, both 10-m and 20-m sprint performances had fully recovered at 5 minutes after stretching. CONCLUSIONS: It is therefore concluded that the acute effects of static, PNF and ballistic stretching may negatively affect sprint performance, although sprint performance is less affected after ballistic stretching than after the other stretching types. Therefore, it is not advisable to perform PNF or static stretching immediately before sprint performance.

Effect of two different kinesio taping techniques on knee kinematics and kinetics in young females.

[Purpose] The application of kinesio taping may improve strength and performance, inhibit and facilitate motor activity, and increase range of motion. The aim of this study was to compare the effects of kinesio taping facilitation and inhibition applications on spatiotemporal knee kinematics and kinetics during walking activity in healthy subjects. [Subjects and Methods] A three-dimensional quantitative gait evaluation was performed without tape and with, facilitation and inhibition kinesio taping application on the knee. Sixteen healthy female college students (age, 19.7 ± 0.4 years; height, 1.64 ± 3.4 cm; body mass, 51.5 ± 4.8 kg) participated in the study. [Results] Spatiotemporal parameters (cadence, walking speed, stride length) were significantly different among the trials. Knee joint sagittal plane range of motion was not different with either kinesio taping application. Knee external flexion moment during the early stance phase decreased significantly with facilitation kinesio taping and increased with the inhibition kinesio taping. Knee external extension moment during the mid-stance phase increased with facilitation kinesio taping. Knee power parameters, eccentric activity in the rectus femoris during the pre-swing phase was significantly increased with inhibition kinesio taping application, while eccentric activity of the hamstrings during the terminal swing of gait was decreased. [Conclusion] These findings showed that facilitation kinesio taping application affected the terminal stance phase and that inhibition kinesio taping influenced the terminal swing phase compared with the no tape condition.

Comparison of Physical and Physiological Profiles in Elite and Amateur Young Wrestlers.

The aim of this study is to examine the physical and physiological determinants of wrestling success between elite and amateur male wrestlers. The wrestlers (N = 126) were first assigned to 3 groups based on their competitive level (top elite, elite, and amateur) and then to 6 groups according to their body mass (light, middle, and heavy weight) and their competitive level (elite and amateur). Top elite and elite wrestlers had significantly (p ≤ 0.05) more training experiences and maximal oxygen uptake compared with the amateur group. In separating weight classes, light- and middle-weight elite (MWE) wrestlers had significantly (p ≤ 0.05) more training experience (7-20%) compared with the light- and middle-weight amateur (MWA) wrestlers. No significant differences were detected between elite and amateur groups (light-, middle-, and heavy-weight wrestlers) for age, body mass, height, body mass index, and body fat (p > 0.05), with the exception of height for heavy wrestlers. Leg average and peak power values (in watts and watts per kilogram) in MWE were higher than MWA (6.5 and 13%, p ≤ 0.05). Relative leg average power value in heavy-weight elite (HWE) (in watts per kilogram) was higher than heavy-weight amateur (HWA) (9.6%, p ≤ 0.05). It was seen that elite wrestlers in MWE and HWE statistically possessed a higher V̇O2max (12.5 and 11.4%, respectively) than amateur middle- and heavy-weight wrestlers (p ≤ 0.05). The results of this study suggest that training experience, aerobic endurance, and anaerobic power and capacity will give a clear advantage for the wrestlers to take part in the elite group.

Physical Fitness Differences between Freestyle and Greco-Roman Junior Wrestlers.

The aim of the present study was to examine physical fitness differences between Freestyle and Greco-Roman junior wrestlers. One hundred twenty-six junior wrestlers, comprising 70 Freestyle and 56 Greco-Roman wrestlers, participated in this study. The somatic and physical fitness profile included body mass, body height, body mass index, body composition, flexibility, maximal anaerobic power of the legs and arms, aerobic endurance, hand grip strength, leg and back strength, and speed. No significant differences were found in the anthropometric and physical features between Freestyle and Greco-Roman wrestlers. The Greco-Roman wrestlers had a significantly higher level of relative leg power, peak arm power, relative peak arm power, and relative average arm power than Freestyle wrestlers (p < 0.05). Greco-Roman wrestlers were significantly faster, had better agility, and had a greater level of leg strength than Freestyle wrestlers, but Freestyle wrestlers were more flexible than Greco-Roman wrestlers (p < 0.05). Discriminant function analysis indicated that peak arm power, agility, speed, and flexibility were selective factors for the differences between Freestyle and Greco-Roman wrestlers. In conclusion, the present study indicates that the differences between these wrestling styles promote physical fitness differences in elite wrestlers. The results reflect specific features of each wrestling style.

Comparative analysis of the 1-mile run test evaluation formulae: assessment of aerobic capacity in male law enforcement officers aged 20-23 years.

OBJECTIVES: The purpose of this study was to compare values of aerobic performance in the 1-mile run test (1-MRT) using different formulae. MATERIAL AND METHODS: Aerobic capacities of 351 male volunteers working for the Turkish National Police within the age range of 20-23 years were evaluated by the 1-MRT and the 20-metre shuttle run (20-MST). VO2max values were estimated by the prediction equations developed by George et al. (1993), Cureton et al. (1995) and Kline et al. (1987) for the 1-MRT and by Leger and Lambert (1982) for the 20-MST. RESULTS: The difference between the results of the different formulae was significant (p = 0.000). The correlation coefficient between the estimated VO2max using Cureton's equation, George's equation, Kline's equation and the 20-MST were 0.691 (p < 0.001), 0.486 (p < 0.001) and 0.608 (p < 0.001), respectively. The highest correlation coefficient was between the VO2max estimated by the 20-MST and Cureton's equation. Similarly, the highest correlation coefficient (r = -0.779) was between the 1-mile run time and the VO2max estimated by Cureton's equation. CONCLUSIONS: When analysing more vigorous exercise than sub-maximal exercise, we suggest that Cureton's equation be used to predict the VO2max from 1-mile run/walk performance in large numbers of healthy individuals with high VO2max. This research compares the use of 3 different formulae to estimate VO2max from 1-mile run/walk performance in male law enforcement officers aged 20-23 years for the first time and reports the most accurate formula to use when evaluating aerobic capacities of large numbers of healthy individuals.

The relationship between body composition, anaerobic performance and sprint ability of amputee soccer players.

The purpose of the present study was to investigate the relationship between body composition, anaerobic performance and sprint performance of amputee soccer players. Fifteen amputee soccer players participated in this study voluntarily. Subjects' height, body weight, body mass index, body fat percentage (Jackson and Pollock formula) and somatotype characteristics (Heath-Carter system) were determined. The sprint performance at 10m, 20m and 30m was evaluated, whereas the counter movement jump (CMJ), relative CMJ (RCMJ), squat jump (SJ) and relative SJ (RSJ) tests were used for the determination of anaerobic performance. The results of the Pearson Product Moment correlation analysis indicated that body composition was significantly correlated with CMJ and SJ (p < 0.01), on the other hand, no measure of body composition was significantly related to the other component (p > 0.05). A significant correlation was found between CMJ, RCMJ, SJ, 10 m, 20 m and 30 m sprint performance (p < 0.05); whereas, in contrast, no measure of body composition was significantly related to the 10 m, 20 m and 30 m sprint performance (p > 0.05). In conclusion, the findings of the present study indicated that sprint performance was described as an essential factor in anaerobic performance whereas body composition and somatotype play a determinant role in anaerobic and sprint performance in amputee soccer players.