Mobility and muscle strength in male former elite endurance and power athletes aged 66−91 years

The aim of this cross‐sectional study was to compare mobility and muscle strength in male former elite endurance and power athletes aged 66?91 years (n = 150; 50 men in both former elite athlete groups and in their control group). Agility, dynamic balance, walking speed, chair stand, self‐rated balance confidence (ABC‐scale), jumping height, and handgrip strength were assessed. Former elite power athletes had better agility performance time than the controls (age‐ and body mass index, BMI‐adjusted mean difference ?3.6 s; 95% CI ?6.3, ?0.8). Adjustment for current leisure time physical activity (LTPA) and prevalence of diseases made this difference non‐significant (P = 0.214). The subjects in the power sports group jumped higher than the men in the control group (age‐ and BMI‐adjusted mean differences for vertical squat jump, VSJ 4.4 cm; 95% CI 2.0, 6.8; for countermovement jump, CMJ 4.0 cm; 95% CI 1.7, 6.4). Taking current LTPA and chronic diseases for adjusting process did not improve explorative power of the model. No significant differences between the groups were found in the performances evaluating dynamic balance, walking speed, chair stand, ABC‐scale, or handgrip strength. In conclusion, power athletes among the aged former elite sportsmen had greater explosive force production in their lower extremities than the men in the control group.     

Similar relative decline in aerobic and anaerobic power with age in endurance and power master athletes of both sexes

Lower physical activity levels in old age are thought to contribute to the age‐related decline in peak aerobic and anaerobic power. Master athletes maintain high levels of physical activity with advancing age and endurance or power training may influence the extent to which these physical functions decline with advancing age. To investigate, 37‐90‐year‐old power (n = 20, 45% female) and endurance (n = 19, 58% female) master athletes were recruited. Maximal aerobic power was assessed when cycling two‐legged (VO₂Peak_2‐leg) and cycling one‐legged (VO₂Peak_1‐leg), while peak jumping (anaerobic) power was assessed by a countermovement jump. Men and women had a similar VO₂Peak_2‐leg (mL/kg/min, P = 0.138) and similar ratio of VO₂Peak_1‐leg to VO₂Peak_2‐leg (P = 0.959) and similar ratio of peak aerobic to anaerobic power (P = 0.261). The VO₂Peak_2‐leg (mL/kg/min) was 17% (P = 0.022) and the peak rate of fat oxidation (FATmax) during steady‐state cycling was 45% higher in endurance than power athletes (P = 0.001). The anaerobic power was 33% higher in power than endurance athletes (P = 0.022). The VO₂Peak_1‐leg:VO₂Peak_2‐leg ratio did not differ significantly between disciplines, but the aerobic to anaerobic power ratio was 40% higher in endurance than power athletes (P = 0.002). Anaerobic power, VO₂Peak_2‐leg, VO₂Peak_1‐leg, and power at FATmax decreased by around 7%‐14% per decade in male and female power and endurance athletes. The cross‐sectional data from 37‐90‐year‐old master athletes in the present study indicate that peak anaerobic and aerobic power decline by around 7%‐14% per decade and this does not differ between athletic disciplines or sexes.     

Aerobic exercise capacity at sea level and at altitude in Kenyan boys, junior and senior runners compared with Scandinavian runners

The aim of this study was to characterize Kenyan runners in regard to their oxygen uptake and blood and ammonia responses when running. Untrained Kenyan boys (14.2±0.2 years) and Scandinavian runners were included for comparison. The studies were performed at altitude (～2.000 m.a.s.l.) and, for several Kenyan and Scandinavian runners, at sea level as well. At altitude sedentary adolescent Kenyan boys had a mean maximal oxygen uptake (Vo_2max) of 47 (44–51) ml · kg^?1· min^?1, whereas similarly aged boys regularly walking or running but not training for competition reached above 62 (58–71) ml · kg^?1· min^?1 in Vo^2max. Kenyan runners in active training had 68±1.4 ml · kg^?1· min^?1 at altitude and 79.9±1.4 ml · kg^?1· min^?1 at sea level, with individuals reaching 85 ml · kg^?1· min^?1. The best Scandinavian runners were not significantly different from the Kenyan runners in Vo_2max both at altitude and at sea level, but none of the Scandinavians reached as high individual values as observed for some Kenyan runners. The running efficiency, determined as the oxygen cost at a given running speed, was less in the Kenyan runners, and the difference became more pronounced when body weight was expressed in ml · kg^?0.75 min^?1. Blood lactate concentration was in general lower in the Kenyan than in the Scandinavian runners, and the Kenyans also had extremely low ammonia accumulation in the blood even at very high exercise intensities. It is concluded that it is the physical activity during childhood, combined with intense training as teenagers that brings about the high Vo_2max observed in some Kenyan runners. Their high aerobic capacity, as well as their good running economy, makes them such superior runners. In addition, their low blood lactate and ammonia accumulation in blood when running may also be contributing factors.     

Stress fracture injury in female endurance athletes in the United Kingdom: A 12‐month prospective study

Studies of stress fracture (SF) incidence are limited in number and geographical location; this study determined the incidence of SF injury in female endurance athletes based in the United Kingdom. A total of 70 athletes aged between 18 and 45 years were recruited and prospectively monitored for 12 months. Questionnaires at baseline and 12 months assessed SF, menstrual and training history, eating psychopathology, and compulsive exercise. Peak lower leg muscle strength was assessed in both legs using an isometric muscle rig. Bone mineral density (BMD) of total body, spine, hip, and radius was assessed using dual X‐ray absorptiometry. Among the 61 athletes who completed the 12‐month monitoring, two sustained a SF diagnosed by magnetic resonance imaging, giving an incidence rate (95% confidence intervals) of 3.3 (0.8, 13.1) % of the study population sustaining a SF over 12 months. The SF cases were 800 m runners aged 19 and 22 years, training on average 14.2 h a week, eumenorrheic with no history of menstrual dysfunction. Case 1 had a higher than average energy intake and low eating psychopathology and compulsive exercise scores, while the reverse was true in case 2. BMD in both cases was similar to mean values in the non‐SF group. The incidence of SF in our female endurance athlete population based in the United Kingdom was 3.3%, which is lower than previously reported. Further work is needed to confirm the current incidence of SF and evaluate the associated risk factors.     

Validity of physical activity and cardiorespiratory fitness in the Danish cohort “Diet,Cancer and Health‐Next Generations”

Valid assessments of physical activity (PA) and cardiorespiratory fitness (CRF) are essential in epidemiological studies to define dose‐response relationship for formulating thorough recommendations of an appropriate pattern of PA to maintain good health. The aim of this study was to validate the Danish step test, the physical activity questionnaire Active‐Q, and self‐rated fitness against directly measured maximal oxygen uptake (VO₂max). A population‐based subsample (n=125) was included from the “Diet, Cancer and Health‐Next Generations” (DCH‐NG) cohort which is under establishment. Validity coefficients, which express the correlation between measured and “true” exposure, were calculated, and misclassification across categories was evaluated. The validity of the Danish step test was moderate (women: r=.66, and men: r=.56); however, men were systematically underestimated (43% misclassification). When validating the questionnaire‐derived measures of PA, leisure‐time physical activity was not correlated with VO₂max. Positive correlations were found for sports overall, but these were only significant for men: total hours per week of sports (r=.26), MET‐hours per week of sports (r=.28) and vigorous sports (0.28) alone were positively correlated with VO₂max. Finally, the percentage of misclassification was low for self‐rated fitness (women: 9% and men: 13%). Thus, self‐rated fitness was found to be a superior method to the Danish step test, as well as being less cost prohibitive and more practical than the VO₂max method. Finally, even if correlations were low, they support the potential for questionnaire outcomes, particularly sports, vigorous sports, and self‐rated fitness to be used to estimate CRF.     

Development of aerobic and anaerobic power in adolescent rowers: a 5‐year follow‐up study

We aimed to determine whether the physical and physiological superiority of early‐maturing rowing athletes, observed at ages 12–13 years, over that of their late‐maturing counterparts observed at the same ages, still persists at 17–18 years of age, when all adolescent athletes are expected to have completed pubertal development. We hypothesized that this superiority of early maturers would not be observed at reassessment, as late maturers would have likely “caught up” with their early‐maturing peers. Twenty‐one male rowers were assessed at age 12.8 ± 0.5 years and again at 17.5 ± 0.5 years (mean ± SD). They were divided into groups of early‐maturing and late‐maturing rowing athletes based on Tanner's sexual maturity ratings. A two‐way repeated‐measures MANOVA followed by a series of ANOVAs with one within‐subject factor (time) and one between‐subject factor (group) indicated significant (P≤0.003) within‐subject and between‐subjects main effects for lean body mass (LBM), maximal oxygen uptake (), and mean power (MP). The group × time interaction effects were significant for LBM (P=0.003), (P=0.004), but not for MP (P=0.171). Over 5 years, early‐maturers' advantage dwindled in terms of LBM (+38% to +9%), (+47% to +9%), and MP (+76% to +15%); however, these differences may still be considered practically relevant. The proposed hypothesis was not supported.     

Physical activity reduces bone loss in the distal forearm in post‐menopausal women – a 25‐year prospective study

Intervention studies have shown that high‐intensity training programs with duration of 1–3 years can influence bone mass in post‐menopausal women. We wanted to investigate whether moderate physical activity could be associated with reduced post‐menopausal bone loss also in the long‐term perspective. We evaluated changes in bone mass and bone structure by repeated single‐photon absorptiometry measurements of the distal forearm in 91 moderately physically active and 21 inactive women, categorized according to information from questionnaires, from menopause and on average 25 years onwards. Data were calculated with analysis of variance and analysis of covariance tests and presented as means with 95% confidence interval. There were no group differences in bone mass or bone structure at menopause. The mean annual loss in bone mineral content was 1.2% (1.1, 1.3) in the physically active and 1.6% (1.3, 1.8) in the inactive women (after adjustment for menopausal age P = 0.02) and the mean decline in a strength index based on bone mass and bone structure was 0.7% (0.6, 0.8) in the physically active and 1.2% (0.8, 1.5) in the inactive women (P = 0.004). There were no group differences in the changes in bone structure. Physical activity is also in a long‐term perspective associated with reduced post‐menopausal bone loss.     

Effects of strength and endurance training on metabolic risk factors in healthy 40–65‐year‐old men

This study compared 21 weeks of combined high‐intensity strength and endurance training with endurance or strength training only on metabolic risk factors in 40–65‐year‐old men. The healthy men (n=63) were randomized into endurance (E), strength (S), combined strength and endurance training (SE) and control (C) groups. S and E trained two times a week and SE 2+2 times a week. Systolic (SBP) and diastolic blood pressure decreased significantly both in E (?6±8 and ?4±6 mmHg) and in S (?9±8 and ?5±7 mmHg), but not in SE or C (P=0.003 for the difference in the changes of SBP between the groups). The changes in serum glucose and insulin during an oral glucose tolerance test did not differ between the groups. Only E decreased serum fasting insulin levels (?17±27%, P=0.013). Minor changes were observed in blood lipids and lipoproteins in all groups. Both endurance and strength training can modestly improve metabolic health even in relatively lean older men with normal glucose tolerance. Combined strength and endurance training did not produce complementary benefits on metabolic risk factors. Combined training is effective in improving body composition and cardiorespiratory and muscular fitness, however, which is likely to decrease the risk of future metabolic and cardiovascular disease.     

Hypertrophic effect of inhaled beta2‐agonist with and without concurrent exercise training: A randomized controlled trial

Due to a high prevalence of asthma and exercise‐induced bronchoconstriction in elite athletes, there is a high use of beta₂‐adrenoceptor agonists (beta₂‐agonists) in the athletic population. While anabolic in rodents, no study has been able to detect hypertrophy in humans after chronic beta₂‐agonist inhalation. We investigated whether inhaled beta₂‐agonist, terbutaline, alters body composition and metabolic rate with and without concurrent exercise training in healthy young men. Sixty‐seven participants completed a 4‐week intervention of daily terbutaline (8 × 0.5 mg) or placebo treatment without concurrent training (habitual; n = 23), with resistance (n = 23) or endurance (n = 21) training 3 times weekly. Before and after the interventions, participant's body composition was determined by dual‐energy X‐ray absorptiometry and resting metabolic rate and substrate oxidation by indirect calorimetry. Terbutaline increased lean body mass by 1.03 kg (95% CI 0.29‐1.76; P  < .05) and 1.04 kg (95% CI 0.16‐1.93; P  < .05) compared to placebo in the habitual and resistance training group, respectively, but had no effect compared to placebo in the endurance training group [−0.56 kg (95% CI −1.74‐0.62; P  > .05)]. Fat mass, bone mineral content, and resting metabolic rate did not change differently between treatments with the intervention. Daily inhalation of terbutaline in near‐therapeutic doses induces skeletal muscle growth. This observation should be a concern for antidoping authorities.     

10‐20‐30 training increases performance and lowers blood pressure and VEGF in runners

The present study examined the effect of training by the 10‐20‐30 concept on performance, blood pressure (BP), and skeletal muscle angiogenesis as well as the feasibility of completing high‐intensity interval training in local running communities. One hundred sixty recreational runners were divided into either a control group (CON; n = 28), or a 10‐20‐30 training group (10‐20‐30; n = 132) replacing two of three weekly training sessions with 10‐20‐30 training for 8 weeks and performance of a 5‐km run (5‐K) and BP was measured. VO_2max was measured and resting muscle biopsies were taken in a subgroup of runners (n = 18). 10‐20‐30 improved 5‐K time (38 s) and lowered systolic BP (2 ± 1 mmHg). For hypertensive subjects in 10‐20‐30 (n = 30), systolic and diastolic BP was lowered by 5 ± 4 and 3 ± 2 mmHg, respectively, which was a greater reduction than in the non‐hypertensive subjects (n = 102). 10‐20‐30 increased VO_2max but did not influence muscle fiber area, distribution or capillarization, whereas the expression of the pro‐angiogenic vascular endothelial growth factor (VEGF) was lowered by 22%. No changes were observed in CON. These results suggest that 10‐20‐30 training is an effective and easily implemented training intervention improving endurance performance, VO_2max and lowering BP in recreational runners, but does not affect muscle morphology and reduces muscle VEGF.     

Stretch‐shortening cycle muscle power in women and men aged 18–81 years: Influence of age and gender

This study explored the age‐related deterioration in stretch‐shortening cycle (SSC) muscle power and concurrent force–velocity properties in women and men across the adult life span. A total of 315 participants (women: n = 188; men: n = 127) aged 18–81 years performed maximal countermovement jumps on an instrumented force plate. Maximal SSC leg extension power expressed per kg body mass (Ppeak) was greater in men than in women across the adult age span (P < 0.001); however, this gender difference was progressively reduced with increasing age, because men showed an ～50% faster rate of decline in SSC power than women (P < 0.001). Velocity at peak power (VPpeak) was greater in men than in women (P < 0.001) but declined at a greater rate in men than in women (P = 0.002). Vertical ground reaction force at peak power (FPpeak) was higher in men than in women in younger adults only (P < 0.001) and the age‐related decline was steeper in men than in women (P < 0.001). Men demonstrated a steeper rate of decline in Ppeak than women with progressive aging. This novel finding emerged as a result of greater age‐related losses in men for both force and velocity. Consequently, maximal SSC power production was observed to converge between genders when approaching old age.     

Cardiorespiratory fitness and health‐related quality of life in women at risk for gestational diabetes

This study examined the associations of cardiorespiratory fitness (CRF ) and leisure‐time physical activity (LTPA ) with health‐related quality of life (HRQ oL) in women at risk for gestational diabetes mellitus (GDM ). The participants were 39 women planning pregnancy with a history of GDM and/or BMI >29 kg/m². We assessed CRF by measuring maximal oxygen consumption (VO _2max) during incremental cycle ergometer exercise until voluntary fatigue. LTPA was self‐reported, and HRQ oL assessed with the SF ‐36 Health Survey (SF ‐36). The mean (SD ) VO _2max was 27 (6) mL·kg⁻¹·min⁻¹, and the mean LTPA was 2.6 (1.7) h/wk. After controlling for BMI , VO _2max was positively associated with the SF ‐36 General Health scale (β 1.27, 95% CI: 0.09, 2.44, P =.035) and the Physical Component Summary (β 0.48, 95% CI: 0.14, 0.82, P =.007). The General Health scale (P =.023) and the Physical Component Summary (P =.011) differed even between those with very poor and poor CRF . After controlling for BMI , LTPA was positively associated with the SF ‐36 Physical Functioning scale (r _s=.34, P =.039), the General Health scale (β 3.74, 95% CI: 0.64, 6.84, P =.020), and the Physical Component Summary (β 1.13 95% CI: 0.19, 2.06, P =.020). To conclude, CRF and LTPA were positively associated with perceived general health and physical well‐being in women planning pregnancy and at risk for GDM . Even a slightly better CRF would be beneficial for well‐being among women with low levels of CRF .     

Altered relationship between R‐R interval and R‐R interval variability in endurance athletes with overtraining syndrome

Autonomic dysfunction decreases within‐subject correlation between R‐R interval length (RRi) and vagally mediated RRi variability in cardiac disease. We tested the hypothesis that overtraining syndrome (OTS) may also weaken this relationship. Nine OTS and 10 control endurance athletes underwent 24‐h electrocardiogram monitoring, which was repeated in eight OTS and nine control athletes after 6 months, when two OTS athletes still had symptoms of OTS. The power of high‐frequency (HF) oscillations of RRi was analyzed in 5‐min epochs over the whole recording. Quadratic regression was performed between 5‐min values of RRi and log‐transformed (ln) HF to obtain R² for each recording. The relationship between RRi and HFln was higher in the OTS athletes than controls [R²: 0.87 (90% confidence interval, CI: 0.84–0.89) vs 0.78 (90% CI: 0.72–0.84); P = 0.034; effect size = 1.22]. Large decrease in R² was observed in six recovered OTS athletes after 6 months follow‐up [ΔR²: ?0.12 (90% CI: ?0.25–0.01); P = 0.11; effect size = 1.44] with no changes in the controls. Mean values of RRi and its variability did not differ between the groups. The within‐subject correlation between RRi and vagally mediated RRi variability was stronger in endurance athletes with OTS compared with controls. The present findings may improve the detection of OTS and recovery from OTS in endurance athletes.     

Construct validity and test–retest reliability of the International Fitness Scale (IFIS) in Spanish children aged 9–12 years

We aimed to examine (a) the construct validity and reliability of the International Fitness Scale (IFIS) in children; and (b) the association of both self‐reported and measured fitness with cardiometabolic risk. Cross‐sectional study in 1145 Spanish children (9–12 years). We measured body fat, waist circumference, blood pressure, lipids, insulin, and fitness level (reported and measured). A validated cardiometabolic syndrome index was used. An age‐ and sex‐matched sample of 245 children originally not included in the study sample fulfilled IFIS twice for reliability purposes. IFIS was able to correctly classify children according to their measured fitness levels (analysis of covariance, adjusted for sex and age was used). Test–retest reliability of IFIS items was also good, i.e., average weighted Kappa = 0.70. Our data also suggest that both measured and reported cardiorespiratory, and speed and agility fitness were associated with cardiometabolic risk factors, such as adiposity and a cardiometabolic syndrome risk score. The associations for muscular fitness (both reported and measured) differed depending on how it was expressed (i.e., absolute vs relative terms). Our findings suggest that self‐reported fitness, as assessed by IFIS, is a valid, reliable, and health‐related measure, and it can be a good alternative at population level when physical fitness cannot be measured.     

Effects of combined endurance and strength training on muscle strength,power and hypertrophy in 40–67‐year‐old men

Both strength and endurance training have several positive effects on aging muscle and physical performance of middle‐aged and older adults, but their combination may compromise optimal adaptation. This study examined the possible interference of combined strength and endurance training on neuromuscular performance and skeletal muscle hypertrophy in previously untrained 40–67‐year‐old men. Maximal strength and muscle activation in the upper and lower extremities, maximal concentric power, aerobic capacity and muscle fiber size and distribution in the vastus lateralis muscle were measured before and after a 21‐week training period. Ninety‐six men [mean age 56 (SD 7) years] completed high‐intensity strength training (S) twice a week, endurance training (E) twice a week, combined training (SE) four times per week or served as controls (C). SE and S led to similar gains in one repetition maximum strength of the lower extremities [22 (9)% and 21 (8)%, P<0.001], whereas E and C showed minor changes. Cross‐sectional area of type II muscle fibers only increased in S [26 (22)%, P=0.002], while SE showed an inconsistent, non‐significant change [8 (35)%, P=0.73]. Combined training may interfere with muscle hypertrophy in aging men, despite similar gains in maximal strength between the strength and the combined training groups.     

Physiological and biological factors associated with a 24 h treadmill ultra‐marathon performance

The purpose of this study was to examine the physiological and biological factors associated with ultra‐endurance performance. Fourteen male runners volunteered to run on a treadmill as many kilometers as possible over a 24‐h period (24TR). Maximal oxygen uptake (V?O_2max), velocity associated with V?O_2max () and running economy (RE) at 8 km/h were measured. A muscle biopsy was also performed in the vastus lateralis muscle. The subjects ran 149.2 ± 15.7 km in 18 h 39 ± 41 min of effective attendance on the treadmill, corresponding to 39.4 ± 4.2% of . Standard multiple‐regression analysis showed that performance was significantly (R²=0.82; P=0.005) related to V?O_2max and specific endurance, i.e. the average speed sustained over the 24TR expressed in . V?O_2max was associated with a high capillary tortuosity (R²=0.66; P=0.01). Specific endurance was significantly related to RE and citrate synthase activity. It is concluded that a high V?O_2max and an associated developed capillary network are essential for ultra‐endurance running performance. The ability to maintain a high %V?O_2max over a 24TR is another factor associated with performance and is mainly related to RE and high mitochondrial oxidative capacity in the vastus lateralis.     

Effects of acute and 2‐week administration of oral salbutamol on exercise performance and muscle strength in athletes

Our objective was to investigate effects of acute and 2‐week administration of oral salbutamol on repeated sprint ability, exercise performance, and muscle strength in elite endurance athletes. Twenty male elite athletes [VO_2max: 69.4 ± 1.8 (Mean ± SE) mL/min/kg], aged 25.9 ± 1.4 years, were included in a randomized, double‐blinded and placebo‐controlled parallel study. At baseline, after acute administration, and again after 2‐week administration of the study drugs (8 mg salbutamol or placebo), subjects' maximal voluntary contraction (MVC) of m. quadriceps and isometric endurance of m. deltoideus were measured, followed by three repeated Wingate tests. Exercise performance at 110% of VO_2max was determined on a bike ergometer. Acute administration of salbutamol increased peak power during first Wingate test by 4.1 ± 1.7% (P < 0.05). Two‐week administration of salbutamol increased (P < 0.05) peak power during first and second Wingate test by 6.4 ± 2.0 and 4.2 ± 1.0%. Neither acute nor 2‐week administration of salbutamol had any effect on MVC, exercise performance at 110% of VO_2max or on isometric endurance. No differences were observed in the placebo group. In conclusion, salbutamol benefits athletes' sprint ability. Thus, the present study supports the restriction of oral salbutamol in competitive sports.     

Relationship between habitual physical activity and gross motor skills is multifaceted in 5‐ to 8‐year‐old children

Adequate motor skills are essential for children participating in age‐related physical activities, and gross motor skills may play an important role for maintaining sufficient level of physical activity (PA) during life course. The purpose of this study was to examine the relationship between gross motor skills and PA in children when PA was analyzed by both metabolic‐ and neuromuscular‐based methods. Gross motor skills (KTK – Körperkoordinationstest für Kinder and APM inventory – manipulative skill test) of 84 children aged 5–8 years (53 preschoolers, 28 girls; 31 primary schoolers, 18 girls) were measured, and accelerometer‐derived PA was analyzed using in parallel metabolic counts and neuromuscular impact methods. The gross motor skills were associated with moderate‐to‐high neuromuscular impacts, PA of vigorous metabolic intensity, and mean level of PA in primary school girls (0.5 < r < 0.7, P < 0.05), and with high impacts in preschool girls (0.3 < r < 0.5, P < 0.05). In preschool boys, moderate impacts, light‐to‐vigorous PA, and mean level of PA were associated with gross motor skills (0.4 < r < 0.7, P < 0.05). In conclusion, the result emphasizes an important relationship between gross motor skills and PA stressing both metabolic and neuromuscular systems in children. Furthermore, PA highly stressing neuromuscular system interacts with gross motor proficiency in girls especially.