Protein Supplementation and Recovery of Muscle Function

The Effect of Milk Derived Protein Supplementation on Muscle Recovery Following Resistance Exercise

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

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