Distribution of concurrent training sessions does not impact endurance adaptation.

OBJECTIVES: Optimized concurrent training regimes are warranted in physical training of military-, law enforcement- and rescue-personnel. This study investigated if four 15-min endurance training sessions weekly improve aerobic capacity and performance more than one 60-min endurance session weekly during the initial phase of a Basic Military Training program. DESIGN: A randomized training intervention study with functional and physiological tests before and after the intervention. METHODS: Military conscripts (n=290) were randomly allocated to three groups completing 9 weeks training. Weekly training consisted of four endurance and four strength training sessions lasting 15min each ('Micro-training': MIC); one strength and one endurance session lasting 60min each ('Classical-training': CLA) or two 60min sessions of standard military training ('Control-training': CON). RESULTS: Both 12-min (∼7-10%) and shuttle run performance (∼35-42%) improved (P≤0.001) similarly in all groups. Likewise, functional 2-min maximal repetition exercise capacity increased (P≤0.05) similarly in all groups (Lunges ∼17-24 %; PushUp ∼10-20%; AbdominalFlexions∼21-23%). Peak oxygen uptake changes depended on group (P≤0.05) with increases (P≤0.01) in MIC (7±7%, n=23) and CON (12±18%, n=17) and no changes in CLA. Maximal m. vastus lateralis citrate synthase activity decreased 14±26% (P≤0.001, n=18) in CLA. Likewise, maximal m. vastus lateralis 3-hydroxyacyl-CoA dehydrogenase activity decreased 8±17% in MIC (n=28) and 14±24% in CLA (n=18). CONCLUSIONS: Four 15-min endurance training sessions weekly improves running performance and strength-endurance similarly to one 60min session. Peak oxygen uptake only increases with more than one endurance session weekly and leg muscle oxidative capacity appears reduced after basic military training.

Recombinant erythropoietin in humans has a prolonged effect on circulating erythropoietin isoform distribution.

The membrane-assisted isoform immunoassay (MAIIA) quantitates erythropoietin (EPO) isoforms as percentages of migrated isoforms (PMI). We evaluated the effect of recombinant human EPO (rhEPO) on the distribution of EPO isoforms in plasma in a randomized, placebo-controlled, double-blinded, cross-over study. 16 healthy subjects received either low-dose Epoetin beta (5000 IU on days 1, 3, 5, 7, 9, 11 and 13); high-dose Epoetin beta (30.000 IU on days 1, 2 and 3 and placebo on days 5, 7, 9, 11 and 13); or placebo on all days. PMI on days 4, 11 and 25 was determined by interaction of N-acetyl glucosamine with the glycosylation dependent desorption of EPO isoforms. At day 25, plasma-EPO in both rhEPO groups had returned to values not different from the placebo group. PMI with placebo, reflecting the endogenous EPO isoforms, averaged 82.5 (10.3) % (mean (SD)). High-dose Epoetin beta decreased PMI on days 4 and 11 to 31.0 (4.2)% (p<0.00001) and 45.2 (7.3)% (p<0.00001). Low-dose Epoetin beta decreased PMI on days 4 and 11 to 46.0 (12.8)% (p<0.00001) and 46.1 (10.4)% (p<0.00001). In both rhEPO groups, PMI on day 25 was still decreased (high-dose Epoetin beta: 72.9 (19.4)% (p=0.029); low-dose Epoetin beta: 73.1 (17.8)% (p=0.039)). In conclusion, Epoetin beta leaves a footprint in the plasma-EPO isoform pattern. MAIIA can detect changes in EPO isoform distribution up til at least three weeks after administration of Epoetin beta even though the total EPO concentration has returned to normal.