Age-related declines in muscle and respiratory function are proportionate to declines in performance in Master Track Cyclists

Purpose Respiratory and musculoskeletal function decline with age, irrespective of physical activity levels. Previous work has suggested that the age-related rate of decline in function of these two systems might be similar, but it is not known to what extent each system contributes to decreasing performance in ageing master cyclists. Therefore, the purposes of this study are (1) whether the age-related rate of decline in respiratory function, respiratory muscle strength, muscle architecture, muscle function, haemoglobin concentration, haematocrit and performance in master cyclists is uniform and (2) which parameters contribute most to the reduction in performance with age. Methods Master cyclists were recruited during the Track Cycling Masters World Championship 2019 in Manchester. Respiratory function and respiratory muscle strength were determined using spirometry and a mouth pressure device, respectively. Muscle architecture was determined using ultrasonography, and muscle function by countermovement jump. Results Forced expiratory volume in the first second, forced vital capacity, fascicle length, muscle thickness, take-off velocity, jump power, jump power per body mass, handgrip strength, haemoglobin concentration and performance correlated negatively with age (p ≤ 0.043). The age-related rate of decline did not differ significantly between parameters (p = 0.124), but it was slower for haemoglobin concentration (p = 0.041). Take-off velocity was the major determinant of performance in 200, 500 and 2000 m track cycling disciplines (R2adj = 0.675, 0.786 and 0.769, respectively; p < 0.001). Conclusion Age-related decline in respiratory and muscle system is accompanied by a similar rate of decline in performance. The major contribution to the age-related decline of performance is reduced muscle function, specifically take-off velocity.

Muscle Function is Associated With Presence, New-onset, or Worsening of Hepatic Steatosis Assessed by Biochemical Parameters, Independent of Muscle Mass

Non-alcoholic fatty liver disease (NAFLD) becomes a major health problem leading to metabolic complications and end-stage liver disease, lacking effective therapeutic interventions. Skeletal muscle deficit, or sarcopenia, is related to accelerated accumulation of ectopic fat at liver. Skeletal muscle can be a novel intervention target of NAFLD. However, previous studies focused on the association between muscle mass and NAFLD, whereas the association of muscle function with NAFLD, a more clinically relevant assessment regarding skeletal muscle, remains unclear. Among participants enrolled between 2013 to 2014 in cardiovascular and Metabolic Diseases Etiology Research Center (CMERC) study (n=807), a cohort of community-dwelling Korean adults to study cardiovascular risk factors, a total of 500 individuals were recruited for 5-year follow-up. Hepatic steatosis was defined by hepatic steatosis index 36 or higher (HSI=8X(AST/ALT)+BMI+2 [if diabetes]+2 [if female]). New-onset of hepatic steatosis was defined as newly developed hepatic steatosis at current follow-up compared to baseline and worsening of HSI was defined as the highest quartile of HSI changes (2 or higher HSI increase). Muscle function was assessed by peak countermovement jump power relative weight (W/kg), 5 times chair rise test (CRT; in seconds), and grip strength (GS; in kg). Appendicular lean mass (ALM) was measured using bioimpedance analysis (InBody770, Biospace, Seoul, Korea). A total of 439 subjects (women 74%; mean age 57 ± 8 year) were analyzed after excluding those with excessive alcohol intake (n=51) and any missing values (n=10). Hepatic steatosis was present in 40% of subjects, which was increased from baseline period (33%, p&lt;0.001). Low peak jump power (adjusted odds ratio [aOR] 1.14 per 1 W/kg decrease), GS (aOR 1.08 per 1kg decrease), and CRT performance (aOR 1.09 per 1 second increase; p&lt;0.05 for all) were all associated with elevated odds of hepatic steatosis, after adjustment for age, gender, height, ALM, and metabolic syndrome components. Compared to those without hepatic steatosis at baseline and follow-up, those with persistent hepatic steatosis had significantly lower jump power in both men and women (33 vs. 40 W/kg in men, p=0.027; 26 vs. 29 W/kg in women, p&lt;0.001). Jump power remained as robust predictor for new-onset hepatic steatosis or worsening of HSI (aOR 1.05 per 1W/kg decrease, p=0.044), whereas GS, CRT, and ALM were not. Muscle function measured by jump power was associated with presence or worsening of hepatic steatosis assessed by biochemical parameters, independent of muscle mass. Acknowledgement: We thank CMERC participants and all research staffs for this work. Funding: This study was supported by research grants from Hanmi Pharmaceutical Co.,Ltd. (4-2018-0845).

Peak vertical jump power predicts radial bone strength better than hand grip strength in healthy individuals.

Osteoporosis is considered a pediatric disease with geriatric consequences. However, measuring bone strength in children is complex and creates a practical problem for health professionals, teachers and parents. A non-invasive measure of muscle fitness that correlates to bone strength may provide a means to monitor bone strength throughout the lifespan. Therefore, the purpose of this study was to investigate the relationship between common muscle function tests (relative grip strength (RGS), peak vertical jump power (PP)) and bone strength in the radial diaphysis and epiphysis of a healthy population. Healthy participants (n=147 (81 female)) performed a bilateral grip strength test using a hand dynamometer, and a maximal vertical jump test. Peak vertical jump power was calculated from maximal jump height using the Sayer’s equation. Moment of inertia (MoI), cortical area (CoA), cortical bone mineral density (cBMD), and polar strength-strain index (SSIp) were measured using peripheral Quantitative Computed Tomography (pQCT) to determine bone strength parameters at the 66% radial site (predominantly cortical bone). At the 4% site (trabecular bone site), bone mineral content (vBMC.tb), bone mineral density (vBMD.tb), total area (ToA.tb) and bone strength index (BSIc) were measured. Hierarchical multiple regression analyses determined the relationship of each muscle function test for each bone envelope (cortical and trabecular). For the cortical bone measurements: RGS, and PP were both significantly correlated with CoA, MoI, and SSIp. Peak vertical jump power predicted bone strength parameters to a greater extent compared to RGS. For the trabecular bone envelope, RGS was not a predictor of bone strength however peak power was a significant predictor of bone strength parameters. Peak vertical jump power was a significant predictor of bone strength at both trabecular and cortical radial sites. Interestingly PP, a lower limb measurement explained the most variance in the bone strength of the upper limb.

Relación del salto contramovimiento y pruebas de velocidad (10-30 m) y agilidad en jóvenes futbolistas chilenos (Relationship of counter-movement jump and speed tests (10-30 m) and agility in young Chilean soccer players)

El objetivo de la presente investigación fue determinar la relación que existe entre el salto contramovimiento y pruebas de velocidad (10-30 m) y agilidad. La muestra estuvo constituida por 169 futbolistas jóvenes entre las categorías sub-13 y sub-19, a los cuales se les aplicó la prueba de salto contramovimiento, velocidad (10-30 m) y agilidad zigzag. Los resultados muestran que la altura del salto contramovimiento presenta una alta correlación negativa con la velocidad 10 m (r=-.693), 30 m (r=-.731) y agilidad (r=-.490). De igual modo, los resultados de la potencia del salto contramovimiento se correlacionan negativamente con la velocidad 10 m (r=-.658), 30 m (r=-.719) y agilidad (r=-.484). Los coeficientes de determinación más altos correspondieron a la altura del salto contramovimiento y velocidad (r2=.534) y la potencia del salto contramovimiento y velocidad (r2=.517). Los resultados obtenidos en el presente estudio sugieren que el salto contramovimiento tiene un alto grado de influencia en el rendimiento en la velocidad (10-30 m), lo cual, parece no estar tan claro en la variable de agilidad. Abstract. The objective of this research was to determine the relationship between countermovement jumping and speed tests (10-30 m) and agility. The sample consisted of 169 young soccer players between the under-13 and under-19 categories, to whom the counter-movement jump test, speed (10-30 m) and zigzag agility were applied. The results show that the height of the countermovement jump shows a high negative correlation with speed 10 m (r = -. 693), 30 m (r = -. 731) and agility (r = -. 490). Similarly, the results of the countermovement jump power are negatively correlated with speed 10 m (r = -. 658), 30 m (r = -. 719) and agility (r = -. 484). The highest coefficients of determination corresponded to the height of the countermovement jump and speed (r2 = .534) and the power of the countermovement jump and speed (r2 = .517). The results obtained in the present study suggest that the countermovement jump has a high degree of influence on speed performance (10-30 m), which seems to be not so clear in the agility variable.