The ability of energy recovery in professional soccer players is increased by individualized low-intensity exercise

Abstract

The aim of this study was to investigate whether individualized low-intensity exercise (ILIE) within the recovery domain before lactate threshold 1 (LT 1) improves energetic recovery and general endurance capacity in professional soccer players. Twenty-four professional soccer players (age: 24.53 ± 4.85 years, height: 180 ± 6.30 cm, body mass: 75.86 ± 8.01 kg, body fat: 12.19 ± 2.69%) participated in the study (n = 24). The 1-h ILIE intervention involved 27 jogging sessions spanning nine weeks and jogging speed corresponding to 72% of LT 1 (7.15 ± 0.95 km∙h−1). Pre-ILIE and post-ILIE LT testing variables measured within 9 weeks included blood lactate concentrations (La−) and heart rate (HR) at specific exercise intensities during ILIE LT test. The jogging/running speeds (S), delta (Δ) S, HR, and ΔHR were measured at 1.5, 2.0, 3.0, and 4.0 mmol∙L−1 La−, respectively. Values of La− and HR at the same exercise intensities (5.4–16.2 km∙h−1) in the post-ILIE LT test compared with pre-ILIE LT test were significantly decreased (P < 0.05 and P < 0.01, respectively). Furthermore, S at all specific La− levels (1.5, 2.0, 3.0, and 4.0) were significantly increased, while HR at 2.0, 3.0, and 4.0 La− decreased significantly (P < 0.05 and P < 0.01, respectively). Low to moderate positive correlations were observed between ΔS and ΔHR at 1.5 and 2.0 La− (r = 0.52 and r = 0.40, respectively). The nine-week ILIE improved energy recovery and general endurance of professional soccer players. This relates to repeated high-intensity intermittent sprints during the 90-min soccer game.

Energetic Contributions Including Gender Differences and Metabolic Flexibility in the General Population and Athletes

“…This anaplerotic mechanism is necessary for gluconeogenesis, lipogenesis, and ATP re-synthesis from lactate during low-intensity exercise in well-trained athletes [ 5 , 10 , 21 , 40 ]. FATox activates crucial enzymes and hormonal responses of gluconeogenesis such as pyruvate kinase, PC, phosphoenolpyruvate carboxykinase, epinephrine, glucagon, cortisol, and other related regulators such as cyclic adenosine monophosphate and intracellular Ca + handling [ 10 , 16 , 17 ]. In these regards, comparisons of CHOox between both groups and negative correlation and regression analyses between La − and FATox support these mechanisms and the differences in mitochondrial function between both groups [ 5 ].…”

“…Previous studies have suggested that high aerobic conditioning comprising an aerobic base such as energy recovery is associated with improved sports performance, cardiometabolic fitness, efficient fat and carbohydrate utilization, and metabolic flexibility in adults and elite athletes. These improvements comprise decreased La − , CHOox, and increased FATox [ 5 , 10 , 13 , 16 , 17 , 21 , 49 ]. Performance-related jogging/running speeds were higher at all steps, and more steps were performed in A than in GP, who utilized higher FATox and lower carbohydrates during GIET.…”

“…The initial jogging speed was 1.5 m∙s −1 , which was increased to 0.5 m∙s −1 every five minutes. The GIET was stopped when La − exceeded 4 mmol∙L −1 after each jogging/running speed in all participants [ 16 , 17 , 25 ]. Capillary blood sampling for lactate and glucose determination was taken from the earlobe (20 µL) immediately after each 5-min step.…”

“…The percentages of estimated maximal HR (HR max ) were calculated using previously described methods [ 16 , 26 ]. The jogging/running speed (S) and HR at 1.5, 2.0, 3.0, and 4.0 mmol∙L −1 La − were analyzed using a previously suggested mathematical model of interpolation [ 16 , 17 , 27 ]. During GIET, oxygen uptake ( O 2 , O 2mean , metabolic equivalents; METs in O 2mean [ 2 , 28 ], and carbon dioxide; CO 2mean ) was measured breath-by-breath, using a mobile gas analyzer MetaMax 3B (Cortex Biophysik, Leipzig, Germany).…”

“…Furthermore, lactate is a simple, efficient, and fast indirect parameter for the calculation of substrate use as mitochondrial function [ 5 , 10 , 16 ]. Previous studies have only indicated La − and oxygen uptake ( O 2 ) levels, and fat and carbohydrate oxidation using stoichiometry in different individuals, which are related to indirect indicators of metabolic flexibility during incremental cycling tests [ 5 , 16 , 17 ]. Furthermore, an analysis of energetic contributions provides information about the physiological responses that are calculated using assessed O 2 and La − values during different exercises in mathematical models [ 18 , 19 , 20 , 21 ].…”