Effect of 2-wk intensified training and inactivity on muscle Na⁺-K⁺pump expression, phospholemman (FXYD1) phosphorylation, and performance in soccer players

Abstract

The present study examined muscle adaptations and alterations in performance of highly trained soccer players with intensified training or training cessation. Eighteen elite soccer players were, for a 2-wk period, assigned to either a group that performed high-intensity training with a reduction in the amount of training (HI, n = 7), or an inactivity group without training (IN, n = 11). HI improved (P < 0.05) performance of the 4th, 6th, and 10th sprint in a repeated 20-m sprint test, and IN reduced (P < 0.05) performance in the 5th to the 10th sprints after the 2-wk intervention period. In addition, the Yo-Yo intermittent recovery level 2 test performance of IN was lowered from 845 +/- 48 to 654 +/- 30 m. In HI, the protein expression of the Na(+)-K(+) pump alpha(2)-isoform was 15% higher (P < 0.05) after the intervention period, whereas no changes were observed in alpha(1)- and beta(1)-isoform expression. In IN, Na(+)-K(+) pump expression was not changed. In HI, the FXYD1ser68-to-FXYD1 ratio was 27% higher (P < 0.01) after the intervention period, and, in IN, the AB_FXYD1ser68 signal was 18% lower (P < 0.05) after inactivity. The change in FXYD1ser68-to-FXYD1 ratio was correlated (r(2) = 0.35; P < 0.05) with change in performance in repeated sprint test. The present data suggest that short-term intensified training, even for trained soccer players, can increase muscle Na(+)-K(+) pump alpha(2)-isoform expression, and that cessation of training for 2 wk does not affect the expression of Na(+)-K(+) pump isoforms. Resting phosphorylation status of the Na(+)-K(+) pump is changed by training and inactivity and may play a role in performance during repeated, intense exercise.

Effect of exercise and training on phospholemman phosphorylation in human skeletal muscle

“…Neither acute exercise nor a 10-day training protocol affected total PLM expression in human skeletal muscle from untrained, sedentary subjects. PLM expression in skeletal muscle was unchanged after 2 wk of intensified training of elite athletes (50). Therefore, it appears that, unlike Na ϩ -K ϩ -ATPase, which was upregulated (Fig.…”

“…Swimming exercise training in rats for 5 days increased PLM phosphorylation on Ser 68 (18). Two weeks of intense training in soccer players increased PLM phosphorylation on Ser 68 (50). These discrepancies might be related to methods used, including wet vs. freeze-dried muscle, species, and training status of the human subjects, and warrants further investigation.…”

“…4), which may be interpreted as an adaptive mechanism in response to increased physical activity, which contributes to enhanced exercise performance (10,20,24,29,32). Several laboratories have also reported this adaptation by the Na ϩ -K ϩ -ATPase ␣ 1 -and ␣ 2 -subunits to different exercise training protocols, including strength training (10), endurance training (35), sprint training (29,32), prolonged cycle training (20), submaximal cycling exercise (22,36), 16 h of heavy intermittent cycle exercise (21), and short-term intense sprint exercise for trained soccer players (50). However, in the present study, we did not detect any statistically significant difference in the expression of the ␣ 3 -subunit of Na (Fig.…”

Muscle variables of importance for physiological performance in competitive football

“…The protein expression was determined as described by Thomassen et al (2010). In short, ~2 mg of the dissected human muscle tissue was homogenized in duplicate for each biopsy (Qiagen Tissuelyser II, Retsch GmbH, Haan, Germany) in a fresh batch of buffer containing (in mM): 10 % glycerol, 20 Na-pyrophosphate, 150 NaCl, 50 HEPES (pH 7.5), 1 % NP-40, 20 β-glycerophosphate, 2 Na3VO4, 10 NaF, 2 PMSF, 1 EDTA (pH 8), 1 EGTA (pH 8), 10 µg/ ml aprotinin, 10 µg/ml leupeptin and 3 benzamidine.…”

Effect of intensified training on muscle ion kinetics, fatigue development, and repeated short-term performance in endurance-trained cyclists

“…In trained subjects intense training would not be expected to change blood flow (24,46), thus any alteration in lactate and H ϩ release may be mediated by changes in transport proteins involved in lactate and H ϩ transport. Changes in MCT1 and NHE1 content in response to intensified training have been reported in some (6,15,18) but not all (3,44) studies in trained runners and soccer players. Thus it is unclear whether intensified training in combination with a reduced training volume induces changes in muscle ion transport proteins involved in lactate and H ϩ transport in trained athletes, and whether these changes leads to alterations in lactate and H ϩ release during intense exercise.…”