Muscle phosphocreatine repletion following single and repeated short sprint efforts

Abstract

Phosphocreatine (PCr) repletion following either single (1x6 s, n=7) or repeated (5x6 s, departing every 30 s, n=8) maximal short sprint cycling efforts was measured in separate groups of trained subjects. Muscle biopsies (vastus lateralis) were taken pre‐exercise before warming up, and then at 10 s, 30 s and 3 min post‐exercise. After the 1 × 6 s sprint PCr concentration was respectively, 55% (10 s; P<0.01), 69% (30 s; P<0.01) and 90% (3 min; NS) of the pre‐exercise value (mean±SD) (81.1±7.4 mmol · kg−1 DM), whereas after the 5 × 6 s sprints, PCr concentration was, respectively, 27% (10 s; P<0.01), 45% (30 s; P<0.01) and 84% (3 min; P<0.01) of the pre‐exercise value (77.1±4.9 mmol · kg−1 DM). PCr concentration was correlated with muscle lactate at 30 s (r=−0.82; P<0.05) and 3 min of recovery (r=−0.94; P<0.01) for the 1 × 6 s sprint, but not for the 5 × 6 s sprints. The extent of PCr repletion was significantly greater after the 5 × 6 s sprints than the 1 × 6 s sprint between both 10 s and 30 s and 30 s and 3 min, despite lower PCr levels at 10 s, 30 s and 3 min following the 5 × 6 s sprints. Full repletion of PCr is likely to take longer after repeated sprints than single short sprints because of a greater degree of PCr depletion, such that replenishment must commence from lower PCr levels rather than because of slower rates of repletion.

Metabolic Conditioning

“…shuttle distances and a short or non-existent rest period resulting in a lack of phosphocreatine (PCr) resynthesis or lactate clearance (26). It may be these issues which contribute to the v20SRT being lower than that found in the 12-min Cooper run …”

“…Furthermore, 15s recovery may allow for sufficient but incomplete restoration of energy substrates such as phosphocreatine (26). The 40m shuttle distance is thought to aid in reducing blood lactate levels compared to the more common 20m…”

Variabilidade Do Desempenho No Line-Drill Test Em Adolescentes Jogadores De Basquetebol

“…Por outro lado será necessário considerar que a duração do esforço no Line-drill Test implica solicitações metabólicas que envolvem, pelo menos em parte, a produção anaeróbica de ATP pela degradação de PCr e glicólise anaeróbica 28 . A relevância do metabolismo anaeróbico no Line-drill Test foi evidente na associação observada com uma prova anaeróbica de 30 s em cicloergómetro em jogadores de basquetebol adolescentes 6 .…”

An Optimal Interset Rest Period For Strength Recovery During A Common Isokinetic Test

“…Gaitanos et al (1993) detected that after a single 6-s maximal cycle sprint, there was a 57% decline (76.5 ± 7.2 to 32.9 ± 2.6 mmol kg -¹) in muscle PCr concentrations. Similarly, Dawson et al (1997) found that after one maximal 6-s cycle sprint, PCr stores were at 55%, 69%, and 90 % of the pre-exercise value at 10-s, 30-s, and 3 minutes post-exercise, respectively. In addition, a comparison was made on the influence of one single maximal cycle sprint (1 x 6-s) vs. a repeated series of cycle sprints (5 x 6-s) on PCr depletion and repletion rates.…”

“…Such an occurrence was the eventual outcome in the findings of Dawson et al (1997) and Gaitanos, Williams, Boobis, & Brooks (1993). Gaitanos et al (1993) detected that after a single 6-s maximal cycle sprint, there was a 57% decline (76.5 ± 7.2 to 32.9 ± 2.6 mmol kg -¹) in muscle PCr concentrations.…”