Case Study: Muscle Atrophy, Hypertrophy, and Energy Expenditure of a Premier League Soccer Player During Rehabilitation From Anterior Cruciate Ligament Injury

Maintaining muscle mass and function during rehabilitation from anterior cruciate ligament (ACL) injury is complicated by the challenge of accurately prescribing daily energy intakes aligned to energy expenditure. Accordingly, we present a 38-week case study characterizing whole body and regional rates of muscle atrophy and hypertrophy (as inferred by assessments of fat free mass from DXA) in a professional male soccer player from the English Premier League. Additionally, in week 6 we also quantified energy intake (via the remote food photographic method) and energy expenditure using the doubly labeled water method. Mean daily energy intake (CHO: 1.9-3.2, Protein: 1.7-3.3 and Fat: 1.4-2.7 g.kg-1) and energy expenditure was 2765 ± 474 and 3178 kcal.d-1 respectively. In accordance with an apparent energy deficit, total body mass decreased by 1.9 kg during week 1-6 where FFM loss in the injured and non-injured limb was 0.9 and 0.6 kg, respectively, yet, trunk FFM increased by 0.7 kg. In weeks 7-28, the athlete was advised to increased daily CHO intake (4-6 g.kg-1) to facilitate an increased daily energy intake. Throughout this period, total body mass increased by 3.6 kg (attributable to a 2.9 and 0.7 kg increase in fat-free and fat mass, respectively). Our data suggest it may be advantageous to avoid excessive reductions in energy intake during the initial 6-8 weeks post-ACL surgery so as to limit muscle atrophy.