Severe Reduction of Energy Availability in Controlled Conditions Causes Poor Endurance Performance, Impairs Explosive Power and Affects Hormonal Status in Trained Male Endurance Athletes

The aim of this study was to severely reduce energy availability (EA) in controlled con- ditions in trained male endurance athletes to observe any effects on health, performance, and psychological and energy markers. EA was reduced by 50% over 14 days in athletes by maintaining identical energy intake and increasing exercise energy expenditure. Blood was drawn, performance was measured by three speci c tests (endurance, explosive power and agility) and two psychologi- cal questionnaires were used. Reduced EA (17.3 5.0 kcal/kg FFM/day) resulted in lower body fat% (t(12) = 3.36,p= 0.006), lower power output and relative power output (t(12) = 2.69,p= 0.021 t(12) = 2.34,p= 0.036), explosive power was reduced (t(12) = 6.41,p= 0.000), lactate metabolism was altered (p= 0.001). EA was negatively correlated with haemoglobin and testosterone (r = 0.557, p= 0.30and r = 0.532,p= 0.037), anaerobic threshold (r = 0.597,p= 0.02) and respiratory com- pensation point (r = 0.575,p= 0.025). There were signi cant differences in Well-being (t(12) = 4.11, p= 0.002) and the Three Factor Eating Questionnaire (t(12) = 2.71,p= 0.020). This is the rst study to demonstrate that endurance performance and explosive power can be affected before detrimental health effects occur in male athletes. Drastic reductions of EA could lead to poor eating behaviours. The two psychological questionnaires seem to be more sensitive to EA changes than blood markers.

This study examines the effects of reduced energy availability on performance in trained male endurance athletes.