Protocol for a randomised controlled trial to investigate the effects of vitamin K2 on recovery from muscle-damaging resistance exercise in young and older adults-the TAKEOVER study.

BACKGROUND: Regular participation in resistance exercise is known to have broad-ranging health benefits and for this reason is prominent in the current physical activity guidelines. Recovery after such exercise is important for several populations across the age range and nutritional strategies to enhance recovery and modulate post-exercise physiological processes are widely studied, yet effective strategies remain elusive. Vitamin K2 supplementation has emerged as a potential candidate, and the aim of the current study, therefore, is to test the hypothesis that vitamin K2 supplementation can accelerate recovery, via modulation of the underlying physiological processes, following a bout of resistance exercise in young and older adults. METHODS: The current study is a two-arm randomised controlled trial which will be conducted in 80 (40 young (≤40 years) and 40 older (≥65 years)) adults to compare post-exercise recovery in those supplemented with vitamin K2 or placebo for a 12-week period. The primary outcome is muscle strength with secondary outcomes including pain-free range of motion, functional abilities, surface electromyography (sEMG) and markers of inflammation and oxidative stress. DISCUSSION: Ethical approval has been granted by the College of Medical Veterinary and Life Sciences Ethical Committee at the University of Glasgow (Project No 200190189) and recruitment is ongoing. Study findings will be disseminated through a presentation at scientific conferences and in scientific journals. TRIAL REGISTRATION: ClinicialTrials.gov NCT04676958. Prospectively registered on 21 December 2020.

Muscle protein synthesis and muscle/metabolic responses to resistance exercise training in South Asian and White European men.

The aims of the current study, therefore, were to compare (1) free-living MPS and (2) muscle and metabolic adaptations to resistance exercise in South Asian and white European adults. Eighteen South Asian and 16 White European men were enrolled in the study. Free-living muscle protein synthesis was measured at baseline. Muscle strength, body composition, resting metabolic rate, VO2max and metabolic responses (insulin sensitivity) to a mixed meal were measured at baseline and following 12 weeks of resistance exercise training. Free-living muscle protein synthesis was not different between South Asians (1.48 ± 0.09%/day) and White Europeans (1.59 ± 0.15%/day) (p = 0.522). In response to resistance exercise training there were no differences, between South Asians and White Europeans, muscle mass, lower body strength or insulin sensitivity. However, there were differences between the ethnicities in response to resistance exercise training in body fat, resting carbohydrate and fat metabolism, blood pressure, VO2max and upper body strength with responses less favourable in South Asians. In this exploratory study there were no differences in muscle protein synthesis or anabolic and metabolic responses to resistance exercise, yet there were less favourable responses in several outcomes. These findings require further investigation.

Blackcurrant extract does not affect the speed-duration relationship during high-intensity running.

Anthocyanin-rich blackcurrant extract (BC) has been shown to ergogenically aid high-intensity exercise. Capacity for such exercise is evaluated by the hyperbolic speed-tolerable duration (S-Dtol) relationship. Therefore, in double-blinded and cross-over randomised controlled trials, 15 males underwent treadmill running incremental exercise testing and were assessed for S-Dtol, quantified by critical speed (CS) and D' (distance), and assessments of time to exhaustion performance to empirically test the limits of the S-Dtol relationship, after daily supplementation of 300 mg/d BC (105 mg/d anthocyanin) or placebo. Supplementation with BC did not change CS (placebo 12.1 ± 1.0 km/h vs BC 11.9 ± 1.0 km/h, p > .05) or D' (placebo 918.6 ± 223.2 m vs BC 965.2 ± 231.2 m, p > .05), although further analysis indicated D' increased in 60% of subject (p = .08), indicating a trend toward cohorts potentially benefiting from BC supplementation. BC supplementation did not change time to exhaustion at or above CS, maximal oxygen uptake (VO2max), lactate threshold (LT), submaximal running economy (CR), or substrate utilisation during exercise (all p > .05). In conclusion, we could not detect any beneficial effect of BC supplementation during high-intensity running exercise, including the determining factors S-Dtol relationship, VO2max, LT or CR. Hence, no ergogenic effect was observed.

Physical and Physiological Determinants of Rock Climbing.

PURPOSE: Rock climbing performance relies on many characteristics. Herein, the authors identified the physical and physiological determinants of peak performance in rock climbing across the range from lower grade to elite. METHODS: Forty four male and 33 female climbers with onsight maximal climbing grades 5a-8a and 5a-7b+, respectively, were tested for physical, physiological, and psychological characteristics (independent variables) that were correlated and modeled by multiple regression and principal component analysis to identify the determinants of rock climbing ability. RESULTS: In males, 23 of 47 variables correlated with climbing ability (P < .05, Pearson correlation coefficients .773-.340), including shoulder endurance, hand and finger strength, shoulder power endurance, hip flexibility, lower-arm grip strength, shoulder power, upper-arm strength, core-body endurance, upper-body aerobic endurance, hamstrings and lower-back flexibility, aerobic endurance, and open-hand finger strength. In females, 10 of 47 variables correlated with climbing ability (P < .05, Pearson correlation coefficients .742-.482): shoulder endurance and power, lower-arm grip strength, balance, aerobic endurance, and arm span. Principal component analysis and univariate multiple regression identified the main explanatory variables. In both sexes, shoulder power and endurance measured as maximum pull-ups, average arm crank power, and bent-arm hang, emerged as the main determinants (P < .01; adjusted R2 = .77 in males and .62 in females). In males, finger pincer (P = .07) and grip strength also had trends (P = .09) toward significant effects. Finally, in test-of-principle training studies, they trained to increase main determinants 42% to 67%; this improved climbing ability 2 to 3 grades. CONCLUSIONS: Shoulder power and endurance majorly determines maximal climbing. Finger, hand, and arm strength, core-body endurance, aerobic endurance, flexibility, and balance are important secondary determinants.

The effect of short-duration resistance training on insulin sensitivity and muscle adaptations in overweight men.

NEW FINDINGS: What is the central question of this study? What is the time course of muscular adaptations to short-duration resistance exercise training? What is the main finding and its importance? Short-duration resistance training results in early and progressive increases in muscle mass and function and an increase in insulin sensitivity. ABSTRACT: The aim of the study was to investigate the effects of 6 weeks of resistance exercise training, composed of one set of each exercise to voluntary failure, on insulin sensitivity and the time course of adaptations in muscle strength/mass. Ten overweight men (age 36 ± 8 years; height 175 ± 9 cm; weight 89 ± 14 kg; body mass index 29 ± 3 kg m-2 ) were recruited to the study. Resistance exercise training involved three sessions per week for 6 weeks. Each session involved one set of nine exercises, performed at 80% of one-repetition maximum to volitional failure. Sessions lasted 15-20 min. Oral glucose tolerance tests were performed at baseline and post-intervention. Vastus lateralis muscle thickness, knee-extensor maximal isometric torque and rate of torque development (measured between 0 and 50, 0 and 100, 0 and 200, and 0 and 300 ms) were measured at baseline, each week of the intervention, and after the intervention. Resistance training resulted in a 16.3 ± 18.7% (P < 0.05) increase in insulin sensitivity (Cederholm index). Muscle thickness, maximal isometric torque and one-repetition maximum increased with training, and at the end of the intervention were 10.3 ± 2.5, 26.9 ± 8.3, 18.3 ± 4.5% higher (P < 0.05 for both) than baseline, respectively. The rate of torque development at 50 and 100 ms, but not at 200 and 300 ms, increased (P < 0.05) over the intervention period. Six weeks of single-set resistance exercise to failure results in improvements in insulin sensitivity and increases in muscle size and strength in young overweight men.