Photobiomodulation therapy is beneficial in reducing muscle fatigue in Brazilian jiu-jitsu athletes and physically active men

Sport Sciences for Health - Photobiomodulation therapy (PBMT) applied prior to exercise may provide ergogenic effects by delaying the onset of fatigue. The Brazilian jiu-jitsu (BJJ) is a domain...     

Effects of six weeks of detraining on retention of functional fitness of old people after nine weeks of multicomponent training

Objectives: To examine the effects of age on functional fitness after six weeks of detraining. Methods: Elderly subjects, aged 60–86 years, completed a nine week multicomponent exercise training programme. They performed the senior fitness test every two weeks during the six week detraining period, and the responses of 12 young-old subjects (YO, aged 60–73 years) and nine older subjects (O, aged 74–86 years) were compared. Results: Functional fitness improved during the exercise training period. Performances in the chair stand and six minute walk for the O group had significantly declined compared with post-training values after two weeks of detraining (p<0.01), whereas there were no significant changes in the YO group. Scores on the functional fitness tests declined further between two and four weeks of detraining in both of the groups (p<0.01). In the YO group, there were significant losses in performance on the chair stand, chair sit and reach, and six minute walk tests, and in the O group on the chair stand and up and go tests after six weeks of detraining compared with after four weeks of detraining (p<0.01). The components of functional fitness most affected by detraining were lower extremity flexibility after two and four weeks of detraining, and agility/dynamic balance after six weeks of detraining. Conclusion: Changes in lower extremity flexibility, up and go, and six minute walk performances in response to six weeks of detraining are affected by age in elderly adults.     

Changes in selected fitness parameters following six weeks of snowshoe training

BACKGROUND: Recently, there has been an increase in popularity and participation in the sport of snowshoeing. While the sport has gained considerable recognition, to date there is little or no scientific research regarding training responses to snowshoeing as a form of exercise. Therefore, the purpose of this study was to determine whether snowshoe training could improve fitness measures. A further purpose was to compare responses from a snowshoe training program to a similarly designed run training program. METHODS: This prospective, comparative study was conducted with healthy males and females between the ages of 19 and 24. These subjects were recruited from the University of Vermont population and surrounding community. Following baseline measurements in VO2max, running time to exhaustion (RTE), and anthropometry, 17 subjects (10 snowshoers and 7 runners) participated in a six week conditioning program. Both groups exercised for 30 min at 75-85% age predicted maximum heart rate, 3-4 times per week, for a total of 18 sessions. RESULTS: VO2max improved significantly in both running and snowshoeing groups, 6.3 and 8.5%, respectively. Run time to exhaustion also improved significantly in both groups, 23.3 and 33.5%, respectively. There were no changes in anthropometry for either group. With the exception of RTE, there were no statistically significant differences between groups in any other measurements at baseline. CONCLUSIONS: These results support the acceptability of snowshoeing as a valid means to improve or maintain cardiovascular endurance.     

Hydroelectrolytic balance of Brazilian jiu-jitsu athletes during a simulated competition

Purpose

To analyze the hydroelectrolytic balance of Brazilian jiu-jitsu athletes during a simulated competition.

Methods

Eight athletes were analyzed in simulated competition (four matches of 10 min). Blood lactate and rating of perceived exertion (6–20 scale) were used to infer the intensity of the matches. Blood samples were taken to determine the serum levels of osmolality, total protein and some electrolytes (chlorides, sodium, potassium, calcium, magnesium, phosphorus and iron).

Results

The lactate concentration changed during the simulated competition (F _7.49 = 35.5; P < 0.001; η ² = 0.85), with an increase post-match compared to the pre-match in matches 1, 2 and 4, but not for match 3. For rating of perceived exertion, no changes were found during the competition (F _3.21 = 9.4; P = 0.440; η ² = 0.12). The matches did not change the osmolality, chlorides, sodium, potassium, magnesium and iron values. For total protein, a difference was observed between the time-points (F _{2.8; 19.6} = 4.6; P = 0.015; η ² = 0.40), with lower concentrations in pre-match 2 than pre-match 1, post-matches 2 and 3. The calcium concentration was also affected by the simulated competition (F _7.49 = 4.0; P = 0.002; η ² = 0.37), with values lower in pre-match 2 than post-matches 1 and 2. The phosphorus serum was changed by matches (F _{3.1; 21.7} = 18.6; P < 0.001; η ² = 0.73), with post-match 1 values higher than the pre-matches 1, 2, 3 and 4 and post-match 3. The pre-match 4 values were lower than post-matches 2 and 4.

Conclusion

Although there were some changes during simulated competition, important alterations in the hydroelectrolytic balance did not occur.

     

Determinants of the training response in elderly men

As part of a prospective randomized trial of the effect of regular exercise in older men, factors determining the magnitude of VO2max increase observed with endurance training were examined in 88 elderly [age 62.9 +/- 3.0 (SD) yr] males. VO2max before and after training was recorded as the highest VO2 observed during two incremental treadmill tests. One year of thrice weekly training sessions increased VO2max (12%, P less than 0.05) in the training group relative to baseline and to a control group (n = 100). The association between the post-training VO2max (VO2max, T2) and the following explanatory variables was assessed using multiple regression analysis: the initial VO2max (VO2max, T1); the reason for stopping the initial treadmill test: leisure time activity during the year previous to the study: the training intensity (speed of walking or running, pulse rate during training, and percentage of heart rate reserve); pulmonary function (forced expiratory volume in 1 s); adiposity (skinfold thickness at 8 sites) and frequency of training. VO2max T1, speed of walking or running during training, reason for stopping the treadmill test, and skinfold thickness were significantly related to post-training VO2max. The intensity and frequency of the training stimulus explained over 10% of the variance in the training effect. Subjects whose test was halted because of fatigue increased VO2max more than those whose test was discontinued for medical or other reasons, even when speed of running was held constant. Previous activity had only a weak effect on training response. The total variance explained by these independent variables was 62%.     

Maximal leg-strength training improves cycling economy in previously untrained men

PURPOSE: This study examined cycling economy before and after 8 wk of maximal leg-strength training. METHODS: Seven previously untrained males (25 +/- 2 yr) performed leg-strength training 3 d.wk(-1) for 8 wk using four sets of five repetitions at 85% of one repetition maximum (1RM). Body mass, lean-leg muscle mass (LLM), percentage of body fat, and leg strength (1RM) were measured at 0, 4, and 8 wk of training. Cycling economy was calculated as the deltaVO2/deltaWR (change in the O2 cost of exercise divided by the change in the power between two different power outputs). RESULTS: There were significant increases in LLM and 1RM from 0 to 4 wk of training (LLM: 25.8 +/- 0.7 to 27.2 +/- 0.8 kg; 1RM: 138 +/- 9 to 215 +/- 9 kg). From 4 to 8 wk of training, 1RM continued to increase significantly (215 +/- 9 to 266 +/- 8 kg) with no further change observed in LLM. Peak power during incremental cycling increased significantly (305 +/- 14 to 315 +/- 16 W), whereas the power output achieved at the gas-exchange threshold (GET) remained unchanged. Peak O2 uptake and the O2 uptake achieved at the GET also remained unchanged following training. Cycling economy improved significantly when the power output was increased from below the GET to above the GET but not for power outputs below the GET. CONCLUSION: Maximal leg-strength training improves cycling economy in previously untrained subjects. Increases in leg strength during the final 4 wk of training with unchanged LLM suggest that neural adaptations were present.     

Effect of 12 weeks of strenuous physical training on hematological changes

It is well known that sports and physical exercise affect the hemoglobin (Hb) concentrations; however, the factors affecting the hematological changes after intense exercise are still not fully elucidated. In the present study, we examined the hematological and biochemical parameters of nine young male soldiers participating in a 12-week ranger training program. The platelet counts before the training showed a strong in-verse correlation with the Hb concentrations after the training (r = -0.829, p < 0.01). Furthermore, the Hb concentrations of the subjects whose platelet counts were more than 25.0 x 10(4)/microL decreased significantly after the training (p < 0.05). Our findings suggest that an association exists between high platelet counts even within the normal range before strenuous physical training and the risk of a subsequent decrease in the Hb concentrations.     

Resistance training improves glycaemic control in obese type 2 diabetic men

The purpose of this investigation was to determine whether moderate intensity resistance training (RT) improves glycaemic control in obese, type 2 diabetic men. Eighteen subjects were randomly assigned to a 10-week RT program, or a non-training control group (C). Glycosylated haemoglobin (HbA 1c ), fasting glucose and insulin, glucose and insulin 120 minutes (2h) after a 75 g oral glucose load, body composition and muscular strength and endurance were measured before and after the 10-week experimental period. In the RT group fasting glucose and insulin decreased with training (p < 0.05) and decreases in HbA 1c approached significance (p = 0.057). 2-h glucose and insulin did not change in either group. Fat free mass (FFM) increased by 3.5 % after RT but was unchanged in the controls. Fat mass (FM) increased 6.9 % in C but was unchanged in RT. Percent body fat was unchanged in both groups. Muscular strength and endurance increased by 25 to 52 % in the RT group but was unchanged in controls. Changes in fasting glucose and HbA 1c were inversely related to changes in FFM. These results suggest that RT is an effective form of exercise training which modestly improves glycaemic control and lowers fasting insulin levels in obese type 2 diabetics.     

Strength training improves muscle aerobic capacity and glucose tolerance in elderly

The primary aim of this study was to investigate the effect of short‐term resistance training (RET) on mitochondrial protein content and glucose tolerance in elderly. Elderly women and men (age 71 ± 1, mean ± SEM) were assigned to a group performing 8 weeks of resistance training (RET, n = 12) or no training (CON, n = 9). The RET group increased in (i) knee extensor strength (concentric +11 ± 3%, eccentric +8 ± 3% and static +12 ± 3%), (ii) initial (0–30 ms) rate of force development (+52 ± 26%) and (iii) contents of proteins related to signaling of muscle protein synthesis (Akt +69 ± 20 and mammalian target of rapamycin +69 ± 32%). Muscle fiber type composition changed to a more oxidative profile in RET with increased amount of type IIa fibers (+26.9 ± 6.8%) and a trend for decreased amount of type IIx fibers (?16.4 ± 18.2%, P = 0.068). Mitochondrial proteins (OXPHOS complex II, IV, and citrate synthase) increased in RET by +30 ± 11%, +99 ± 31% and +29 ± 8%, respectively. RET resulted in improved oral glucose tolerance measured as reduced area under curve for glucose (?21 ± 26%) and reduced plasma glucose 2 h post‐glucose intake (?14 ± 5%). In CON parameters were unchanged or impaired. In conclusion, short‐term resistance training in elderly not only improves muscular strength, but results in robust increases in several parameters related to muscle aerobic capacity.     

Maximum heart rate predicted by formulas versus values obtained in graded exercise tests in Brazilian jiu-jitsu athletes

Introduction

Aerobic training can be conducted using the maximum heart rate (HRmax) target zone. This type of training is relevant to improving aerobic fitness and can help Brazilian jiu-jitsu athletes maintain optimal performance during and between matches. However, due to the lack of specificity of the generic equations in systematizing the training, the values can be overestimated, because athletes show specific morphophysiological adjustments.

Objective

The aim was to investigate the relationship between HRmax as estimated by means of formulas and HRmax as reached in graded exercise tests (GTX) in both the laboratory and the field.

Methods

13 male Brazilian jiu-jitsu athletes had their HRmax determined in GTX on the treadmill and in the field, and the HRmax was calculated based on FOX and TANAKA equations.

Results

The HRmax value by the means equation FOX-HRmax (189?±?6 bpm) was greater in comparison with the GTX (on treadmill: 183?±?7 bpm; field test: 180?±?10 bpm; p?<?0.05). The equation TANAKA-HRmax (185?±?4 bpm) showed higher values when compared to the field test (180?±?10 bpm; p?<?0.05). No differences were observed between TANAKA-HRmax and GTX on the treadmill (p?>?0.05). The correlation observed was between FOX-HRmax and TANAKA-HRmax: (r?=?0.99; p?<?0.01).

Conclusion

FOX-HRmax and TANAKA-HRmax tend to overestimate the results compared to GTX. Thus, HRmax equations should be used and analyzed with caution. Conducting GTX is recommended to establish accurate values of HR.

     

Resistance training alters torque-velocity relation of elbow flexors in elderly men

PURPOSE: The aim of the study was to compare in vivo dynamic muscle characteristics (torque-velocity relation and maximal contraction velocity) of sedentary young subjects with elderly men before and after training. METHODS: Elbow flexion maximal isometric (Tmax) and dynamic torque at velocities between 100 degrees.s-1 and 600 degrees.s-1 were measured, from which maximal contraction velocity was estimated (eVmax). These parameters were obtained from 18 young sedentary subjects (Y) and from 23 healthy sedentary elderly (mean age 63 yr) men (E) before (PRE), after 13 wk (MID), and 26 wk (POST) of moderate intensity resistance training (30RM) of the elbow flexor muscles. RESULTS: Y and E before training had similar Tmax, but mean dynamic torque over all velocities was 49.1% higher in Y compared with E. After 13 wk of training TmaxE increased by 8.2% and mean dynamic torque increased by 61.2%, with a velocity dependent gain. For eVmaxE an increase of 21.8% was observed. The second 13-wk training period did not induce further increases. CONCLUSION: The results of the present study demonstrate that, after moderate intensity resistance training of healthy elderly men, maximal contraction velocity of elbow flexors (eVmax), estimated from the torque-velocity curve, increased to values observed for sedentary young men.     

Neural adaptations after 4 years vs 12 weeks of resistance training vs untrained

The purpose of this study was to compare the effect of resistance training (RT) duration, including years of exposure, on agonist and antagonist neuromuscular activation throughout the knee extension voluntary torque range. Fifty‐seven healthy men (untrained [UNT] n = 29, short‐term RT [12WK] n = 14, and long‐term RT [4YR] n = 14) performed maximum and sub‐maximum (20%‐80% maximum voluntary torque [MVT]) unilateral isometric knee extension contractions with torque, agonist and antagonist surface EMG recorded. Agonist EMG, including at MVT, was corrected for the confounding effects of adiposity (ie, muscle‐electrode distance; measured with ultrasonography). Quadriceps maximum anatomical cross‐sectional area (QACSA_MAX; via MRI) was also assessed. MVT was distinct for all three groups (4YR +60/+39% vs UNT/12WK; 12WK +15% vs UNT; 0.001 < P ≤ 0.021), and QACSA_MAX was greater for 4YR (+50/+42% vs UNT/12WK; [both] P < 0.001). Agonist EMG at MVT was +44/+33% greater for 4YR /12WK ([both] P < 0.001) vs. UNT, but did not differ between RT groups. The torque‐agonist EMG relationship of 4YR displayed a right/down shift with lower agonist EMG at the highest common torque (196 Nm) compared to 12WK and UNT (0.005 ≤ P ≤ 0.013; Effect size [ES] 0.90 ≤ ES ≤ 1.28). The torque‐antagonist EMG relationship displayed a lower slope with increasing RT duration (4YR < 12WK < UNT; 0.001 < P ≤ 0.094; 0.56 ≤ ES ≤ 1.31), and antagonist EMG at the highest common torque was also lower for 4YR than UNT (?69%; P < 0.001; ES = 1.18). In conclusion, 4YR and 12WK had similar agonist activation at MVT and this adaptation may be maximized during early months of RT. In contrast, inter‐muscular coordination, specifically antagonist coactivation was progressively lower, and likely continues to adapt, with prolonged RT.     

Effect of floorball training on blood lipids,body composition,muscle strength,and functional capacity of elderly men

Floorball training consists of intense repeated exercise and may offer a motivating and social stimulating team activity in elderly individuals. However, the effect of floorball training in elderly adults on physiological adaptations important for health is not known. Thus, this study examined the effect of floorball training on blood lipids, muscle strength, body composition, and functional capacity of men aged 65–76 years. Thirty‐nine recreational active men were randomized into a floorball group (FG; n = 22) or petanque group (PG; n = 17), in which training was performed 1 h twice a week for 12 weeks. In FG and PG, average heart rate (HR) during training was 80% and 57%, respectively, of maximal HR. In FG, plasma low‐density lipoprotein (LDL) cholesterol and triglycerides were 11% and 8% lower (P < 0.05), respectively. Insulin resistance determined by homeostatic model assessment (HOMA‐IR) was reduced (P < 0.05) by 18%. HR during submaximal cycling was 5% lower (P < 0.05), and maximal voluntary contraction force was 8% higher (P < 0.05). Total and visceral fat content was lowered (P < 0.05) by 5% and 14%, respectively, HR at rest was 8% lower (P < 0.05) and performance in four different functional capacity tests were better (P < 0.05) after compared to before the training period. No changes were observed in PG. In conclusion, 12 weeks of floorball training resulted in a number of favorable effects important for health and functional capacity, suggesting that floorball training can be used as a health‐promoting activity in elderly men.     

Enhanced satellite cell proliferation with resistance training in elderly men and women

In addition to the well-documented loss of muscle mass and strength associated with aging, there is evidence for the attenuating effects of aging on the number of satellite cells in human skeletal muscle. The aim of this study was to investigate the response of satellite cells in elderly men and women to 12 weeks of resistance training. Biopsies were collected from the m. vastus lateralis of 13 healthy elderly men and 16 healthy elderly women (mean age 76+/-SD 3 years) before and after the training period. Satellite cells were visualized by immunohistochemical staining of muscle cross-sections with a monoclonal antibody against neural cell adhesion molecule (NCAM) and counterstaining with Mayer's hematoxylin. Compared with the pre-training values, there was a significant increase (P<0.05) in the number of NCAM-positively stained cells per fiber post-training in males (from 0.11+/-0.03 to 0.15+/-0.06; mean+/-SD) and females (from 0.11+/-0.04 to 0.13+/-0.05). These results suggest that 12 weeks of resistance training is effective in enhancing the satellite cell pool in skeletal muscle in the elderly.     

Effects of CrossFit training on lipid profiles,body composition and physical fitness in overweight men

Sport Sciences for Health - The aim of this study was to investigate the influence of the CrossFit training on cardiovascular risk factors in overweight men. Twenty-six overweight men (age,...