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To determine (a) the impact of ischemic preconditioning pressures (applied as a % of arterial occlusion pressure [AOP]) on pressure pain threshold (PPT) and resistance exercise performance and (b) whether changes in performance could be explained by changes in PPT. Subjects (n539) completed 4 protocols in a randomized order: (a) ischemic preconditioning (IPC) at 110% AOP (IPC 110%), (b) IPC at 150% AOP (IPC 150%), (c) IPC at 10% AOP (Sham), and (d) time-matched control (CON). Each protocol included 4 cycles of 5 minutes of occlusion followed by 5 minutes of reperfusion. Pressure pain threshold was taken before and after. Discomfort ratings were given at the end of each cycle. Every visit finished with 2 sets of 75-second maximal isokinetic unilateral elbow flexion or extension. Overall, IPC 110% and IPC 150% resulted in similar increases in PPT relative to CON [110%: difference of 0.36 (0.18, 0.54) kg·m-2; 150%: difference of 0.377 (0.15, 0.59) kg·m-2] and Sham. Both resulted in greater discomfort than Sham and CON, with IPC 150% inducing greater discomfort than IPC 110% (BF10: 14.74). There were no differences between the conditions for total work (BF10: 0.23), peak torque (BF10: 0.035), or average power (BF10: 0.159). We did not find evidence that PPT mediated performance. We did not detect changes in performance with 2 different relative pressures greater than AOP. Our mean applied pressures were lower than those used previously. There might be a minimal level of pressure (e.g., >150% of AOP) that is required to induce ergogenic effects of ischemic preconditioning. [ABSTRACT FROM AUTHOR]

Objective: Handgrip strength may differ depending on the type of sport played during the developmental period. Youth sports in which athletes hold equipment in their hands may be the most effective for improving handgrip strength. This study aimed to examine the age at which differences in handgrip strength appear by comparing sports that involve gripping (kendo) with those that do not involve gripping (soccer) in young athletes. Methods: Two hundred and twenty‐two male athletes (115 kendo and 107 soccer) between 6 and 15 years old participated in this study. Handgrip strength was measured using a dynamometer, and the average value of both hands was used for analysis. Sports experience was determined when they started practicing each sport. Handgrip strength was compared between sports. Statistical moderation was used to determine if the relationship between sport and handgrip strength depended upon the age of the athlete. Results: Kendo athletes had significantly higher handgrip strength than soccer athletes (4.77 kg [95% CI: 2.34, 7.19]) in the overall sample. We found that the relationship between sport and handgrip strength depended upon the age of the child (sport*age t = −3.6, p =.004). Using the Johnson‐Neyman procedure, we found statistically significant differences between sports from 8.48 years and older. Conclusions: Our results suggest that the type of sport played, that is, whether or not an athlete plays with sports equipment in their hands, may influence the development of handgrip strength during the period of growth, and these sports may contribute to a higher level of handgrip strength in adulthood. [ABSTRACT FROM AUTHOR]

IntroductionShort leukocyte telomere length (LTL) has become a hallmark characteristic of aging. Some, but not all, evidence suggests that physical activity (PA) may play an important role in attenuating age-related diseases and may provide a protective effect for telomeres. The purpose of this study was to examine the association between PA and LTL in a national sample of US adults from the National Health and Nutrition Examination Survey.MethodsNational Health and Nutrition Examination Survey data from 1999 to 2002 (n = 6503; 20-84 yr) were used. Four self-report questions related to movement-based behaviors (MBB) were assessed. The four MBB included whether individuals participated in moderate-intensity PA, vigorous-intensity PA, walking/cycling for transportation, and muscle-strengthening activities. An MBB index variable was created by summing the number of MBB an individual engaged in (range, 0-4).ResultsA clear dose-response relation was observed between MBB and LTL; across the LTL tertiles, respectively, the mean numbers of MBB were 1.18, 1.44, and 1.54 (Ptrend < 0.001). After adjustments (including age) and compared with those engaging in 0 MBB, those engaging in 1, 2, 3, and 4 MBB, respectively, had a 3% (P = 0.84), 24% (P = 0.02), 29% (P = 0.04), and 52% (P = 0.004) reduced odds of being in the lowest (vs highest) tertile of LTL; MBB was not associated with being in the middle (vs highest) tertile of LTL.ConclusionsGreater engagement in MBB was associated with reduced odds of being in the lowest LTL tertile.

Objectives: (1) To examine the muscle thickness of various muscle groups of the body to estimate the absolute and relative skeletal muscle mass (SM) in competitive physique‐based athletes (Bodybuilding, 212 Bodybuilding, Bikini, and Physique divisions) and (2) to compare values across various divisions of competition and to resistance trained and non‐resistance trained individuals. Methods: Eight competitive physique‐based athletes (2 M and 6 F), two recreationally resistance trained (1 M and 1 F) and two non‐resistance trained (1 M and 1 F) participants had muscle thickness measured by ultrasound at nine sites on the anterior and posterior aspects of the body. SM was estimated from an ultrasound‐derived prediction equation and SM index was used to adjust for the influence of standing height (i.e., divided by height squared). Results: SM values ranged from 19.6 to 60.4 kg in the eight competitive physique‐based athletes and 16.1 to 32.6 kg in the four recreationally resistance trained and non‐resistance trained participants. SM index ranged from 7.2 to 17.9 kg/m2 in the eight competitive physique‐based athletes and 5.8 to 9.3 kg/m2 in the four recreationally resistance trained and non‐resistance trained participants. Conclusion: Overall, varying magnitudes of SM and SM index were present across competitors and their respective divisions of bodybuilding. The Men's Open Bodybuilder in the present study had greater values of total SM and SM index compared to previously published values in the literature. Our data provides insight into the extent of SM present in this population and further extends the discussion regarding SM accumulation in humans. [ABSTRACT FROM AUTHOR]

Purpose: To 1) examine whether blood flow restriction would provide an additional exercise-induced hypoalgesic response at an upper and lower limb when it is incorporated with low-load resistance exercise until failure, and 2) examine if increases in blood pressure and discomfort, with blood flow restricted exercise, would mediate the exercise-induced hypoalgesia over exercise without blood flow restriction. Methods: Forty healthy young participants completed two trials: four sets of unilateral knee extension exercise to failure at 30% of one-repetition maximum, with and without blood flow restriction. Pressure pain thresholds were assessed before (twice) and 5-min post exercise at an upper and lower limb. Blood pressure and discomfort ratings were recorded to examine mediating effects on exercise-induced hypoalgesia with blood flow restricted exercise. Results: Pressure pain threshold increased following both exercise conditions compared to a control, without any differences between exercise conditions at the upper (exercise conditions vs. control: ~0.37 kg/cm²) and lower (exercise conditions vs. control: ~0.60 kg/cm²) limb. The total number of repetitions was lower for exercise with blood flow restriction compared to exercise alone [median difference (95% credible interval) of -27.0 (-29.8, -24.4) repetitions]. There were no mediating effects of changes in blood pressure, nor changes in discomfort, for the changes in pressure pain threshold at either the upper or lower limb. Conclusion: The addition of blood flow restriction to low-load exercise induces a similar hypoalgesic response to that of non-blood flow restricted exercise, with a fewer number of repetitions. [ABSTRACT FROM AUTHOR]