Protein Supplementation and Recovery of Muscle Function

The focus is performance nutrition. Resistance exercise can induce low level muscle damage in conjunction with impaired contractile function. Milk-derived proteins contain, or induce, bioactive properties that assist muscle recovery and restore/improve muscle function. The aim of the research is the recovery of muscle function following resistance exercise.

In this study, the investigators propose to undertake a comparison of the ingestion of two milk-derived protein-based recovery drinks on muscle function after resistance exercise compares to an isonitrogenous, non-essential amino acid control.

Study Design: A block randomised design of 3 groups of resistance-exercise trained (RET) men

Participants: 24 young, healthy, resistance exercise trained, males aged 18 - 35 years.

Recovery drinks; CONTROL - an isonitrogenous, non-essential amino acid solution; PROTEIN - a milk-based whey protein concentrate (WPC), WPC-80; HYDROLYSATE - a hydrolysed derivative of WPC-80.

Day 1, Pre-screening consisting of:

* medical history and examination by a clinician
* blood sample to be evaluated for health-related contraindications
* body composition measurement by dual energy x-ray absorptiometry (DXA) to determine whole body and segmental lean tissue mass;
* exercise training log (6 month recall);
* dietary consultation;
* habitual physical activity level assessed by European Physical Activity Questionaire (EPAQ)-2

Day 2 - 8: Participants will be "free-living" during this time. Participants will record dietary intake under the guidance of a qualified dietitian and sports nutritionist.

Day 9 and 10: Participants will complete two familiarisation sessions to the resistance exercise and muscle function testing procedures.

A single blood sample (5ml) will be drawn following o/n fast on each day. On day 2 participants will drink a metered dose of deuterated water (around 200ml) containing deuterium. A saliva sample will be taken before and after consuming this bolus.

Day 11-17. During this experimental phase diet is prescribed and provided. The diet is based on habitual food intake standardized to body mass.

Day 11: O/n fasted blood, saliva and 1st micro-biopsy of muscle obtained; Muscle function measured prior to and upon completion of a prescribed bout of resistance exercise training (RET); The recovery drink (0.33 g protein/kg body mass) is ingested; 3 hours following completion of RET a 2nd micro-biopsy of muscle is obtained.

Day 12: O/n fasted blood and saliva is obtained Muscle function measured and recovery drink (0.33 g protein/kg body mass) consumed.

Day 13: O/n fasted blood and saliva is obtained Muscle function measured followed by the 2nd RET bout and recovery drink (0.33 g protein/kg body mass) consumed.

Day 14: O/n fasted blood and saliva is obtained Muscle function measured and recovery drink (0.33 g protein/kg body mass) consumed.

Day 15: O/n fasted blood and saliva is obtained Muscle function measured followed by the 3rd RET bout and recovery drink (0.33 g protein/kg body mass) consumed.

Day 16 O/n fasted blood, saliva and 3rd micro-biopsy of muscle obtained Muscle function measured and recovery drink (0.33 g protein/kg body mass) consumed.

Day 17: O/n fasted blood and saliva is obtained Muscle function measured

Eligibility Criteria:
Inclusion Criteria:

* risk
* no known current illness or physically active
* resistance-exercise trained
* no known intolerance to milk-based products
* no known blood born disease or medication that would adversely affect participation
* no adverse risk to venepuncture

Exclusion Criteria:

• recent musculoskeletal injury