Effects of recovery time on phosphocreatine kinetics during repeated bouts of heavy-intensity exercise

Forbes, Sean C.; Raymer, Graydon H.; Kowalchuk, John M.; Thompson, R. Terry; Marsh, Greg D.

doi:10.1007/s00421-008-0762-2

Cited by 34 publications

(34 citation statements)

References 46 publications

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“…The value for moderate exercise in the control condition of the present study (ϳ15 s) was somewhat smaller than we (32) and others (3,4,55) have reported previously (ϳ23-35 s) but similar to the values that have been considered to be realistic for moderate exercise (52). On the other hand, the value for heavy exercise in the control condition of the present study (ϳ55 s) was similar to or somewhat greater than we (29,30,32) and others (14,56,57) have reported previously (38 -54 s). The explanation for the substantial slowing of [PCr] kinetics between moderate-and heavy-intensity exercise in the present study and also in an earlier study from our laboratory (32) is obscure but might be related to our experimental protocol, which involves unilateral concentric/eccentric knee extension exercise, potentially resulting in high muscle tension development during high-intensity exercise and consequent impairments to muscle blood flow and oxygenation (30).…”

Section: Discussionsupporting

confidence: 86%

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Jones¹,

Wilkerson²,

Fulford³

2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Jones AM, Wilkerson DP, Fulford J. Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans. Am J Physiol Regul Integr Comp Physiol 296: R1078 -R1087, 2009. First published February 11, 2009 doi:10.1152/ajpregu.90896.2008.-We hypothesized that increasing skeletal muscle total creatine (Cr) content through dietary Cr supplementation would result in slower muscle phosphocreatine concentration ([PCr]) kinetics, as assessed using 31 P magnetic resonance spectroscopy, following the onset and offset of both moderateintensity (Mod) and heavy-intensity (Hvy) exercise. Seven healthy males (age 29 Ϯ 6 yr, mean Ϯ SD) completed a series of square-wave transitions to Mod and Hvy knee extensor exercise inside the bore of a 1.5-T superconducting magnet both before and after a 5-day period of Cr loading (4ϫ 5 g/day of creatine monohydrate). Cr supplementation resulted in an ϳ8% increase in the resting muscle oxygen uptake kinetics; respiratory control; creatine kinase; muscle energetics; 31 P magnetic resonance spectroscopy MEYER'S "ELECTRICAL ANALOG" model of respiratory control posits that the time constant () for the exponential fall in muscle phosphocreatine concentration ([PCr]) following the onset of muscle contractions is a function of the mitochondrial resistance and the metabolic capacitance (45). The model predicts that an increase in mitochondrial density will result in a shorter (that is, faster [PCr] kinetics) and that an increase in metabolic capacitance, determined predominantly by the muscle total creatine (Cr) content, will result in a longer (slower [PCr] kinetics). In keeping with this prediction, Meyer and colleagues reported that increased citrate synthase activity induced by endurance training resulted in faster [PCr] kinetics in rat muscle (49) and that depletion of the total Cr content of rat gastrocnemius muscle, achieved through 8 wk of feeding with the Cr analog ␤-guanidinopropionic acid, resulted in significantly faster [PCr] (1,9,42,47). In an important recent study, Kindig et al. (35) reported that acute CK inhibition led to a significantly faster fall in intracellular PO 2 (equivalent in this model to a faster rise in V O 2 ) following the onset of contraction in isolated Xenopus myocytes. Moreover, Glancy et al. (16) demonstrated that the for oxygen consumption in isolated mitochondria was linearly related to the total Cr content in the incubation medium.Collectively, these data provide strong support for the notion that the for both muscle [PCr] and V O 2 conforms to a simple linear model of respiratory control, at least under the conditions of the experiments performed. In humans, however, data relating [PCr] and/or V O 2 kinetics to the muscle total Cr content are sparse. Francescato et al. (15) recently reported that intersubject differences in resting muscle [PCr] were positively correlated (r ϭ 0.71) with the for the fall in [PCr] during plantar flexion exercise in humans. However, the range of resting [PCr] values ...

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Section: Discussionsupporting

confidence: 86%

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Jones¹,

Wilkerson²,

Fulford³

2009

American Journal of Physiology-Regulatory, Integrative and Comp

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“…This was similar to the effect of prior exercise on subsequent bouts of exercise reported previously (6,29,34). In the present study, for example, during the human high-intensity protocol there was a significant time effect (P ϭ 0.015) observed when comparing the lowest pH obtained during each repeated cycle, with the first cycle having a lower pH compared with the subsequent repeated bouts (cycle 1: pH 6.77 Ϯ 0.05; cycles 2-5: pH range 6.86 Ϯ 0.02 to 6.89 Ϯ 0.02).…”

Section: Preliminary Analysis Of Ph and Pcrsupporting

confidence: 90%

Phosphocreatine recovery kinetics following low- and high-intensity exercise in human triceps surae and rat posterior hindlimb muscles

Forbes¹,

Paganini²,

Slade³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Forbes SC, Paganini AT, Slade JM, Towse TF, Meyer RA. Phosphocreatine recovery kinetics following low-and high-intensity exercise in human triceps surae and rat posterior hindlimb muscles. Am J Physiol Regul Integr Comp Physiol 296: R161-R170, 2009. First published October 22, 2008 doi:10.1152/ajpregu.90704.2008.-Previous studies have suggested the recovery of phosphocreatine (PCr) after exercise is at least second-order in some conditions. Possible explanations for higher-order PCr recovery kinetics include heterogeneity of oxidative capacity among skeletal muscle fibers and ATP production via glycolysis contributing to PCr resynthesis. Ten human subjects (28 Ϯ 3 yr; mean Ϯ SE) performed gated plantar flexion exercise bouts consisting of one contraction every 3 s for 90 s (low-intensity) and three contractions every 3 s for 30 s (highintensity). In a parallel gated study, the sciatic nerve of 15 adult male Sprague-Dawley rats was electrically stimulated at 0.75 Hz for 5.7 min (low intensity) or 5 Hz for 2.1 min (high intensity) to produce isometric contractions of the posterior hindlimb muscles. [31 P]-MRS was used to measure relative [PCr] changes, and nonnegative leastsquares analysis was utilized to resolve the number and magnitude of exponential components of PCr recovery. Following low-intensity exercise, PCr recovered in a monoexponential pattern in humans, but a higher-order pattern was typically observed in rats. Following high-intensity exercise, higher-order PCr recovery kinetics were observed in both humans and rats with an initial fast component ( Ͻ 15 s) resolved in the majority of humans (6/10) and rats (5/8). These findings suggest that heterogeneity of oxidative capacity among skeletal muscle fibers contributes to a higher-order pattern of PCr recovery in rat hindlimb muscles but not in human triceps surae muscles. In addition, the observation of a fast component following high-intensity exercise is consistent with the notion that glycolytic ATP production contributes to PCr resynthesis during the initial stage of recovery. oxidative capacity; fiber types; skeletal muscle; magnetic resonance spectroscopy; nonnegative least-squares analysis THE TIME COURSE OF PHOSPHOCREATINE (PCr) recovery following exercise is often characterized by using a monoexponential model (18,21,26,37). A monoexponential pattern is consistent with a first-order metabolic system in which PCr resynthesis is entirely dependent on ATP produced by oxidative phosphorylation (11, 21) with the inverse of the time constant (tau, ) or rate constant (1/) directly proportional to muscle oxidative capacity (19,26). Specifically, the rate constant of PCr resynthesis has been shown to be directly proportional to citrate synthase activity (which reflects mitochondrial content) and inversely proportional to total creatine content (20, 26). Nevertheless, multiexponential PCr recovery kinetics have been commonly reported after high-intensity exercise (1,10,23,31,32,41). Although the factor(s) contributing to this higher-order response have...

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“…In this leg position the SOL muscle is expected to be involved more than the two gastrocnemii 20. This second examination was performed at least 20 min after the first one, to ensure sufficient metabolic recovery 36. Two additional spiral‐MRSI measurements were performed at rest in two of these subjects in order to acquire representative flip angle maps37 in both leg positions.…”

Section: Methodsmentioning

confidence: 99%

Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

et al. 2016

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Phosphorus MRSI (31P–MRSI) using a spiral‐trajectory readout at 7 T was developed for high temporal resolution mapping of the mitochondrial capacity of exercising human skeletal muscle.The sensitivity and localization accuracy of the method was investigated in phantoms. In vivo performance was assessed in 12 volunteers, who performed a plantar flexion exercise inside a whole‐body 7 T MR scanner using an MR‐compatible ergometer and a surface coil. In five volunteers the knee was flexed (~60°) to shift the major workload from the gastrocnemii to the soleus muscle.Spiral‐encoded MRSI provided 16–25 times faster mapping with a better point spread function than elliptical phase‐encoded MRSI with the same matrix size. The inevitable trade‐off for the increased temporal resolution was a reduced signal‐to‐noise ratio, but this was acceptable. The phosphocreatine (PCr) depletion caused by exercise at 0° knee angulation was significantly higher in both gastrocnemii than in the soleus (i.e. 64.8 ± 19.6% and 65.9 ± 23.6% in gastrocnemius lateralis and medialis versus 15.3 ± 8.4% in the soleus).Spiral‐encoded 31P–MRSI is a powerful tool for dynamic mapping of exercising muscle oxidative metabolism, including localized assessment of PCr concentrations, pH and maximal oxidative flux with high temporal and spatial resolution.

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Effects of recovery time on phosphocreatine kinetics during repeated bouts of heavy-intensity exercise

Cited by 34 publications

References 46 publications

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Phosphocreatine recovery kinetics following low- and high-intensity exercise in human triceps surae and rat posterior hindlimb muscles

Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

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Effects of recovery time on phosphocreatine kinetics during repeated bouts of heavy-intensity exercise

Cited by 34 publications

References 46 publications

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Phosphocreatine recovery kinetics following low- and high-intensity exercise in human triceps surae and rat posterior hindlimb muscles

Dynamic 31P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

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Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T