Little is known on the human adaptation to extreme endurance and with the increasing popularity in long duration events we seek to provide insight into the physiological and metabolic adaptation processes of ocean rowing.

Rowing 12-18 hours a day will illicit a high energy expenditure and anecdotally people have lost large amounts of body weight and variable amounts of muscle mass, particularly in the lower limbs. This may provide insights and a potential new model to to study muscle unloading.

Previous research has investigated factors determining muscle loss through bed rest and limb immobilisation. These methods are limited in that some do not include inflammation or changes in nutrition, which have been shown to be key drivers of muscle loss. These studies aim to investigate a potentially new model of muscle unloading.

Ocean rowing is an ultra-endurance sport where people spend 35-90 days at sea. Usually rowing for a minimum of 12 hours a day, in a 2-hour on/off shift pattern with daily food rations. Rowers lose body and muscle mass. There is likely to be low-grade inflammation, nutritional deficit, fatigue and rowers do not stand up for the entire crossing. Part 1 aims to quantify this muscle loss by inviting rowers in the annual 3000 mile Talisker Whisky Atlantic Challenge 2020 to take part. While part 2 aims to continue the work by measuring upper and core muscles as well as lower limb muscles from the first study with the aim of understanding how the body allocates resources in a hypocaloric, high energy expenditure environment.

Muscle mass of the lower limbs of the rowers will be measured with ultrasound, as well as body mass, body composition, energy expenditure and nutritional intake, the week before the race and immediately after arrival in Antigua. As well as adding novel insights to the knowledge base around factors affecting ultra endurance performance, the results will then be used to inform future intervention studies aimed at preventing muscle loss.

Inclusion Criteria:

- Taking part in the Talisker Whisky Atlantic Challenge 2020 and 2021

Exclusion Criteria:

- lower limb amputee musculoskeletal, metabolic, neurological disease pacemaker fitted

Healthy, fit and active males and females aged 18 and over

no plan to share IPD