111 research outputs found
Acute cardiovascular responses during resistance exercise: comparison between chronic heart failure patients, healthy age matched and young subjects
Acute hemodynamic responses during resistance efforts are not well characterized. The aim of the present project was to characterize
such responses during lower limb resistance exercise, in different population
Preconditioning effect of heavy exercise on O2 uptake kinetics, determined as MRT (mean response time), in chronic heart failure patients
It has been demonstrated that oxygen consumption kinetics (VO2cin) at the onset of aerobic exercise may be speeded up when preceded by a short bout of heavy exercise (preconditioning heavy exercise,PHE). It was proposed that the mechanism underlying PHE be related to increased muscle blood flow and heart rate after heavy exercise, which would speed up the enhancement of oxygen transport to active muscle after PHE
Cardiac, vascular and metabolic changes during recovery from resistance effort
The aim of the present project was to characterize cardiovascular changes combined with O2 utilisation during and after resistance efforts, such as weight-lifting, in young subjects
Strength asymmetries are muscle-specific and metric-dependent
We investigated if dominance affected upper limbs muscle function, and we calculated the level of agreement in asymmetry direction across various muscle-function metrics of two heterologous muscle groups. We recorded elbow flexors and extensors isometric strength of the dominant and non-dominant limb of 55 healthy adults. Participants performed a series of explosive contractions of maximal and submaximal amplitudes to record three metrics of muscle performance: maximal voluntary force (MVF), rate of force development (RFDpeak), and RFD-Scaling Factor (RFD-SF). At the population level, the MVF was the only muscle function that showed a difference between the dominant and non-dominant sides, being on average slightly (3-6%) higher on the non-dominant side. At the individual level, the direction agreement among heterologous muscles was poor for all metrics (Kappa values ≤ 0.15). When considering the homologous muscles, the direction agreement was moderate between MVF and RFDpeak (Kappa = 0.37) and low between MVF and RFD-SF (Kappa = 0.01). The asymmetries are muscle-specific and rarely favour the same side across different muscle-performance metrics. At the individual level, no one side is more performative than the other: each limb is favoured depending on muscle group and performance metric. The present findings can be used by practitioners that want to decrease the asymmetry levels as they should prescribe specific exercise training for each muscle
Futsal and Continuous Exercise Induce Similar Changes in Specific Skeletal Muscle Signalling Proteins
Exercise elicits skeletal-muscle adaptations which are important for improved health outcomes. We compared the effects of a futsal game (FUT) and moderate-intensity continuous exercise (MOD), on the skeletal-muscle protein signalling responses in young, healthy individuals. 16 men undertook an incremental exercise test and a resting muscle biopsy performed >48\u2009h apart. They were then randomly allocated to either FUT (n=12) consisting of 2\u2009x\u200920\u2009min halves, or MOD (n=8) consisting of a work-matched running bout performed at an intensity corresponding to the individual ventilatory threshold 1. Work matching was achieved by means of triaxial accelerometers. Immediately after FUT and MOD, participants underwent a second biopsy to assess exercise-induced changes in protein signalling. Total and phosphorylated protein abundance was assessed via western blotting. Both FUT and MOD altered signalling responses in skeletal muscle. FUT increased total ATF2 protein abundance (p=0.048) and phosphorylation (p=0.029), while no changes occurred with MOD. Both exercise regimes increased ACC phosphorylation (p=0.01) and returned a trend for increased p38MAPK phosphorylation. Futsal may be employed as an alternative to continuous exercise to elicit muscle adaptations which may be associated with improved health outcomes. As only FUT increased ATF2 activation, this protein might be a target of future investigation on exercise-induced signalling
In vivo and in vitro evidence that intrinsic upper- and lower-limb skeletal muscle function is unaffected by ageing and disuse in oldest-old humans
Aim: To parse out the impact of advanced ageing and disuse on skeletal
muscle function, we utilized both in vivo and in vitro techniques to comprehensively
assess upper- and lower-limb muscle contractile properties in
8 young (YG; 25 6 years) and 8 oldest-old mobile (OM; 87 5 years)
and 8 immobile (OI; 88 4 years) women.
Methods: In vivo, maximal voluntary contraction (MVC), electrically
evoked resting twitch force (RT), and physiological cross-sectional area
(PCSA) of the quadriceps and elbow flexors were assessed. Muscle biopsies
of the vastus lateralis and biceps brachii facilitated the in vitro assessment
of single fibre-specific tension (Po).
Results: In vivo, compared to the young, both the OM and OI exhibited
a more pronounced loss of MVC in the lower limb [OM (60%) and OI
(75%)] than the upper limb (OM = 51%; OI = 47%). Taking into
account the reduction in muscle PCSA (OM = 10%; OI = 18%), only
evident in the lower limb, by calculating voluntary muscle-specific force,
the lower limb of the OI (40%) was more compromised than the OM
(13%). However, in vivo, RT in both upper and lower limbs (approx.
9.8 N m cm
2) and Po (approx. 123 mN mm
2), assessed in vitro, implies
preserved intrinsic contractile function in all muscles of the oldest-old and
were well correlated (r = 0.81).
Conclusion: These findings suggest that in the oldest-old, neither
advanced ageing nor disuse, per se, impacts intrinsic skeletal muscle function,
as assessed in vitro. However, in vivo, muscle function is attenuated
by age and exacerbated by disuse, implicating factors other than skeletal
muscle, such as neuromuscular control, in this diminution of function.
Keywords in vitro, in vivo, oldest-old, sarcopeni
Concomitant ventilatory and circulatory functions of the diaphragm and abdominal muscles
Similar cardiovascular and autonomic responses in trained type 1 diabetes mellitus and healthy participants in response to half marathon
Futsal and continuous exercise induce similar changes in specific skeletal muscle signalling proteins
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