Central and regional circulatory adaptations to one-leg training

Klausen, Kurt Klaudi; Secher, Nells; Clausen, Jan; Hartling, O. J.; Trap‐Jensen, J.

doi:10.1152/jappl.1982.52.4.976

Cited by 150 publications

(180 citation statements)

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“…First, within both individual muscles and muscle groups, both oxygen uptake and maximum aerobic force production are consistently greater when the exercise engages a lesser total mass of muscle (5,15,50,53). Previous results from the many one-vs. two-legged cycle ergometry and knee-extension studies indicate greater aerobic force production occurs via higher rates of oxygen uptake in the working muscle (35,51), rather than through the recruitment of synergist muscles. Supporting this, during onelegged knee-extensions neuromuscular activity has been found to be absent in synergistic muscle groups at work rates up to the aerobic maximum (5).…”

Section: Discussionmentioning

confidence: 95%

A metabolic basis for impaired muscle force production and neuromuscular compensation during sprint cycling

Bundle

Ernst²,

Bellizzi³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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For both different individuals and modes of locomotion, the external forces determining all-out sprinting performances fall predictably with effort duration from the burst maximums attained for 3 s to those that can be supported aerobically as trial durations extend to roughly 300 s. The common time course of this relationship suggests a metabolic basis for the decrements in the force applied to the environment. However, the mechanical and neuromuscular responses to impaired force production (i.e., muscle fatigue) are generally considered in relation to fractions of the maximum force available, or the maximum voluntary contraction (MVC). We hypothesized that these duration-dependent decrements in external force application result from a reliance on anaerobic metabolism for force production rather than the absolute force produced. We tested this idea by examining neuromuscular activity during two modes of sprint cycling with similar external force requirements but differing aerobic and anaerobic contributions to force production: one-and two-legged cycling. In agreement with previous studies, we found greater peak per leg aerobic metabolic rates [59% (Ϯ6 SD)] and pedal forces at V O2 peak [30% (Ϯ9)] during one-vs. two-legged cycling. We also determined downstroke pedal forces and neuromuscular activity by surface electromyography during 15 to 19 all-out constant load sprints lasting from 12 to 400 s for both modes of cycling. In support of our hypothesis, we found that the greater reliance on anaerobic metabolism for force production induced compensatory muscle recruitment at lower pedal forces during twovs. one-legged sprint cycling. We conclude that impaired muscle force production and compensatory neuromuscular activity during sprinting are triggered by a reliance on anaerobic metabolism for force production. motor control; aerobic and anaerobic contributions; performance HUMAN LOCOMOTOR PERFORMANCE depends directly upon the forces that the musculoskeletal system can generate and transmit to the environment. For example, runners and cyclists modulate their speed and power output primarily by altering the respective forces they apply to the ground (61) or pedals (29). The maximum external forces applied at top running speed or at peak cycling power output can be supported by skeletal muscle for only 3 s or less (41, 61). As the duration of all-out efforts become more prolonged, the external forces that the musculoskeletal system can provide become progressively reduced. As a result, performances decline from the 3-s maximum to a nearly sustainable level as the duration of all-out efforts extends to 300 s (10, 17, 30). The reductions in force production responsible for the well-characterized performanceduration relationship have been considered by some investigators to be a whole-body manifestation of muscle fatigue (9, 62). Given the rapidity with which the duration-dependent decrements in force production occur, shorter-duration, all-out efforts provide a potentially powerful approach for examining the time co...

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Section: Discussionmentioning

confidence: 95%

A metabolic basis for impaired muscle force production and neuromuscular compensation during sprint cycling

Bundle

Ernst²,

Bellizzi³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Ceretelli et al (1984) have shown that the xenon clearance method may underestimate muscle blood flow by as much as 2-fold. From the results reported by Clausen and associates (Clausen, Klausen, Rasmussen & Trap-Jensen, 1973;Secher, Clausen, Klausen, Noer & Trap-Jensen, 1977;Klausen et al 1982) it appears that when a large percentage of the muscle mass is involved in the exercise (arm work added to leg work or two-legged instead of one-legged exercise) resistance in vessels of the exercising limbs is also increased.…”

Section: Discussionmentioning

confidence: 99%

“…However, most tracer-dilution methods are not directly applicable to the present study. Some of the concerns we had were that in flow measurements using bolus injections of tracer or cold saline (Hosie, 1962;Jorfeldt, Juhlin-Dannfelt, Pernow & Wassen, 1978;S0rlie & Myhre, 1977;Klausen, Secher, Clausen, Hartling & Trap-Jensen, 1982) one obvious general problem is the fluctuations in blood flow during dynamic exercise. Multiple randomized measurements which are averaged may compensate for this.…”

Section: Discussionmentioning

confidence: 99%

Maximal perfusion of skeletal muscle in man.

Andersen¹,

Saltin²

1985

The Journal of Physiology

1,055

905

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SUMMARY1. Five subjects exercised with the knee extensor of one limb at work loads ranging from 10 to 60 W. Measurements of pulmonary oxygen uptake, heart rate, leg blood flow, blood pressure and femoral arterial-venous differences for oxygen and lactate were made between 5 and 10 min of the exercise.2. Flow in the femoral vein was measured using constant infusion of saline near 0 'C. Since a cuff was inflated just below the knee during the measurements and because the hamstrings were inactive, the measured flow represented primarily the perfusion of the knee extensors.3. Blood flow increased linearly with work load right up to an average value of 57 1 min-. Mean arterial pressure was unchanged up to a work load of 30 W, but increased thereafter from 100 to 130 mmHg. The femoral arterial-venous oxygen difference at maximum work averaged 14-6 % (v/v), resulting in an oxygen uptake of 0-80 1 min-. With a mean estimated weight of the knee extensors of 2-30 kg the perfusion of maximally exercising skeletal muscle of man is thus in the order of 2-5 1 kg-' min', and the oxygen uptake 0-35 1 kg-' min-. 4. Limitations in the methods used previously to determine flow and/or the characteristics ofthe exercise model used may explain why earlier studies in man have failed to demonstrate the high perfusion of muscle reported here.5. It is concluded that muscle blood flow is closely related to the oxygen demand of the exercising muscles. The hyperaemia at low work intensities is due to vasodilatation, and an elevated mean arterial blood pressure only contributes to the linear increase in flow at high work rates. The magnitude of perfusion observed during intense exercise indicates that the vascular bed of skeletal muscle is not a limiting factor for oxygen transport.

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“…The knee extension exercise allows isolation of a specific muscle group (quadriceps), which appears to be particularly susceptible to age-related loss of oxidative capacity (Conley et al 2000). As in the present study, the single-limb training model has been used to differentiate between effects due to O 2 transport and those due to O 2 utilisation and/or diffusion of O 2 from the capillaries to the mitochondria (Davies & Sargeant, 1975;Saltin et al 1976;Henriksson, 1977;Thomas et al 1981;Klausen et al 1982;Hardman et al 1987) although none of these studies have examined on-transient V O 2 kinetics. The advantage of using older subjects, with slow initial V O 2 kinetics, is that larger changes in V O 2 kinetics are elicited with training (Babcock et al 1994b), and thus it is easier to determine the relative importance of oxygen delivery versus utilisation in determining V O 2 kinetics.…”

mentioning

confidence: 99%

Determinants of Oxygen Uptake Kinetics in Older Humans Following Single‐Limb Endurance Exercise Training

Bell

Paterson

Kowalchuk

et al. 2001

Experimental Physiology

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The kinetics of oxygen uptake (V O 2 ) during the on-transient of moderate-intensity exercise have been shown to be slowed with ageing (Bell et al. 1999) and slower in untrained relative to trained adults (Chilibeck et al. 1996). Following 6 months of endurance exercise training, the kinetics of V O 2 in older men were appreciably accelerated (Babcock et al. 1994b) during cycle ergometer exercise, but it was unclear whether this acceleration was due to improved O 2 transport, increased mitochondrial capacity or a combination of both of these adaptations. In the present study we utilised a single-leg knee extension training model in order to gain information pertinent to the control of V O 2 kinetics in older men. This method of exercise allows use of Doppler technology to measure mean blood velocity (Shoemaker et al. 1994(Shoemaker et al. , 1996aRichardson et al. 1995Richardson et al. , 1999Richardson & Saltin, 1998). The knee extension exercise allows isolation of a specific muscle group (quadriceps), which appears to be particularly susceptible to age-related loss of oxidative capacity (Conley et al. 2000). As in the present study, the single-limb training model has been used to differentiate between effects due to O 2 transport and those due to O 2 utilisation and/or diffusion of O 2 from the capillaries to the mitochondria (Davies & Sargeant, 1975;Saltin et al. 1976;Henriksson, 1977;Thomas et al. 1981;Klausen et al. 1982;Hardman et al. 1987) although none of these studies have examined on-transient V O 2 kinetics. The advantage of using older subjects, with slow initial V O 2 kinetics, is that larger changes in V O 2 kinetics are elicited with training (Babcock et al. 1994b), and thus it is easier to determine the relative importance of oxygen delivery versus utilisation in determining V O 2 kinetics. Additionally, in studying ageing it is important to determine the mechanisms of the limitations to exercise, and thus potential interventions to stimulate specific adaptations.If, following single-leg knee extension training, the kinetics of V O 2 were accelerated in the untrained (as well as the trained) leg, then this would imply that the acceleration is due to an adaptation to compensate for a limitation in O 2 delivery (Hughson et al. 1996). However, if V O 2 kinetics were accelerated in the trained leg only, then these data would support the possibility of improved blood flow to the exercising limb, enhanced diffusion of O 2 or improvement in metabolic function (Grassi et al. 1996). We measured mean blood velocity (MBV) in the femoral artery as an indicator of

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Central and regional circulatory adaptations to one-leg training

Cited by 150 publications

References 0 publications

A metabolic basis for impaired muscle force production and neuromuscular compensation during sprint cycling

A metabolic basis for impaired muscle force production and neuromuscular compensation during sprint cycling

Maximal perfusion of skeletal muscle in man.

Determinants of Oxygen Uptake Kinetics in Older Humans Following Single‐Limb Endurance Exercise Training

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