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The present study examined the effects of repetitive hopping training on muscle activation profiles and fascicle–tendon interaction in the elderly. 20 physically active elderly men were randomly assigned for training (TG) and control groups (CG). TG performed supervised bilateral short contact hopping training with progressively increasing training volume. Measurements were performed before the training period (BEF) as well as after 2 weeks (2 W) and 11 weeks (11 W) of training. During measurements, the gastrocnemius medialis–muscle (GaM) fascicle and its outer Achilles tendon length changes during hopping were examined by ultrasonography together with electromyographic (EMG) activities of calf muscles, kinematics, and kinetics. At 2 W, the ankle joint stiffness was increased by 21.0 ± 19.3 % and contact time decreased by 9.4 ± 7.8 % in TG. Thereafter, from 2–11 W the jumping height increased 56.2 ± 18.1 % in TG. Simultaneously, tendon forces increased 24.3 ± 19.0 % but tendon stiffness did not change. GaM fascicles shifted to shorter operating lengths after training without any changes in their length modifications during the contact phase of hopping. Normalized EMG amplitudes during hopping did not change with training. The present study shows that 11 W of hopping training improves the performance of physically active elderly men. This improvement is achieved with shorter GaM operating lengths and, therefore, increased fascicle stiffness and improved tendon utilization after training. Based on these results, hopping training could be recommended for healthy fit elderly to retain and improve rapid force production capacity.

This study examined the effect of bovine colostrum (BC) supplementation on the tissue composition of resistance trained (T) and untrained (UT) limbs. Using a double-blind design, subjects were randomly allocated to 60 g day−1 of BC (n=17) or whey protein (WP) (n=17) during 8 weeks of resistance training of the elbow flexors (EF) of their non-dominant arm (T). Axial magnetic resonance images of both upper arms, maximal voluntary isometric torque (MVC) of EF, and the one repetition maximum (1RM) for bicep curls were measured pre- and post-supplementation. There were no differences in macronutrient intakes (P>0.28) or the volume of training completed by T (P=0.98) between the two groups. T of BC experienced a significantly greater increase in circumference [BC 2.3 (3.0)%, WP 0.0 (4.2)%; P=0.05] and cross-sectional area (CSA) [BC 4.2 (6.0)%, WP −0.2 (8.3)%; P=0.05] compared with WP, due principally to a greater increase in skin and subcutaneous fat (SSF) CSA [BC 5.5 (10.9)%, WP −2.7 (14.1)%; P=0.03]. No tissue compartment changed significantly in UT of either group (P>0.05). MVC and 1RM increased for T and UT in both groups (P<0.05), but the increases were not different between groups (P>0.32). Since the SSF compartment increased in T but not UT, and fat turnover in adipocytes is under hormonal control and would not be localised to one arm, we suggest that the increase in SSF CSA in T of BC may have been due to an increase in skin CSA, rather than fat.

An 89 Versuchspersonen (50 Sportlern und 39 Nichtsportlern) wurden physikalische Kreislaufanalysen nachBroemsee u.Ranke vorgenommen. Die Leistungsfähigkeit der Versuchspersonen wurde mit Hilfe der Leistungskapazität bei 170 Pulsen/min (PWC170) und mit der maximalen O2-Aufnahme nach dem Astrand-Ryhming-Nomogramm getestet. Es ergaben sich signifikante Beziehungen (p < 0,001) zwischen dem Körpergewicht und der Herzfrequenz, dem Herzminutenvolumen, dem Herzminutenvolumen pro Kilogramm Körpergewicht, der Herzleistung, dem Gefäßwiderstand und der Diastolendauer einerseits und der Leistungskapazität (PWC170) und der maximalen Sauerstoffaufnahme andererseits. Die straffste Beziehung wurde gefunden zwischen dem Minutenvolumen/Kilogramm Körpergewicht in Ruhe und der PWC170 mit einem Korrelationskoeffizienten r = −0,76. Die Messung des Minutenvolumens/Kilogramm Körpergewicht gestattet somit gewisse Aussagen über die körperliche Leistungsfähigkeit. Ein geringes Minutenvolumen/ Kilogramm Körpergewicht spricht für eine hohe Leistungsfähigkeit und ein hohes Minutenvolumen/Kilogramm Körpergewicht für eine geringe Leistungsfähigkeit. Die Ursache für die Verknüpfung von Ruhekreislaufwerten und Leistungsfähigkeit wird in der dem jeweiligen Trainingszustand entsprechenden Kreislaufökonomie gesehen.

Es wird die Arbeitsweise eines zur Bestimmung des systolischen und diastolischen Druckes im wachen Zustand geeigneten Apparates sowie das Prinzip der Messung beschrieben.

This study investigated cycling performance and oxygen uptake $$( \dot{V}{\text{O}}_{ 2} )$$ kinetics between upright and two commonly used recumbent (R) postures, 65°R and 30°R. On three occasions, ten young active males performed three bouts of high-intensity constant-load (85% peak-workload achieved during a graded test) cycling in one of the three randomly assigned postures (upright, 65°R or 30°R). The first bout was performed to fatigue and second and third bouts were limited to 7 min. A subset of seven subjects performed a final constant-load test to failure in the supine posture. Exercise time to failure was not altered when the body inclination was lowered from the upright (13.1 ± 4.5 min) to 65°R (10.5 ± 2.7 min) and 30°R (11.5 ± 4.6 min) postures; but it was significantly shorter in the supine posture (5.8 ± 2.1 min) when compared with the three inclined postures. Resulting kinetic parameters from a tri-exponential analysis of breath-by-breath $$ \dot{V}{\text{O}}_{ 2} $$ data during the first 7 min of exercise were also not different between the three inclined postures. However, inert gas rebreathing analysis of cardiac output revealed a greater cardiac output and stroke volume in both recumbent postures compared with the upright posture at 30 s into the exercise. These data suggest that increased cardiac function may counteract the reduction of hydrostatic pressure from upright ~25 mmHg; to 65°R ~22 mmHg; and 30°R ~18 mmHg such that perfusion of active muscle presumably remains largely unchanged, and also therefore, $$ \dot{V}{\text{O}}_{ 2} $$ kinetics and performance during high-intensity cycling.

Considerable debate exists as to whether increases in strength that occur with resistance exercise are the result of increases in muscle size. Most studies have attempted to answer this question using assessments of whole muscle size and voluntary muscle strength, but examining changes at the individual muscle fiber level may also provide some insight. The purpose of this meta-analysis was to compare adaptations at the whole muscle and individual fiber level. A meta-analysis was conducted in February, 2018 including all previously published papers and was analyzed using a random effects model. There were no differences (p = 0.88) when comparing hypertrophy at the whole muscle (4.6%) and individual fiber level (7.0%), but significantly larger (p < 0.001) strength gains were observed at the whole muscle level (43.3%) relative to the individual fiber (19.5%). Additionally, there was an increase in the specific tension of type 1 muscle fibers (p = 0.013), but not type 2 muscle fibers (p = 0.23) which was driven by similar increases in strength (type 1: 17.5%, type 2A: 17.7%), despite differences in muscle size (type 1: 6.7%, type 2A: 12.1%). These results support the hypothesis that the neural adaptations play a large role in increasing isotonic whole muscle strength, but also demonstrate that an improvement in specific tension of type 1 muscle fibers is present. These results would suggest that some mechanism intrinsic to the muscle fiber, and independent of muscle growth, may also be contributing to strength increases in response to resistance exercise providing an avenue for future research.