The influence of leucine supplementation and resistance training on body composition and muscle characteristics in healthy elderly.

Ageing is accompanied with a reduced muscle protein synthesis, which is an
important cause of the strong decline in skeletal muscle mass and function.
This process results in a reduction in physical performance, a loss of
functional capacity and an increased likelihood of developing type 2 diabetes,
obesity, osteoporosis and cardiovascular diseases in elderly.

The most effective stimulus for muscle protein synthesis is physical activity,
especially resistance training. However, for resistance exercise to be
effective (i.e. resulting in net protein accretion), the sufficient
availability of amino acids as precursors seems to be a decisive determinant.
Therefore, post-exercise protein intake is an important factor.

There is also evidence that ingestion of additional leucine, a precursor of
proteins, can result in an increased muscle mass and function without physical
activity.

In part A, we study the influence of ingestion of additional leucine on body
composition, muscle function and plasma glucose responses.

In part B, we study the influence of the timing of post-exercise protein intake
on the effectiveness of the exercise intervention.

In part A, 2 groups of healthy elderly will perform a 12 week placebo
controlled trial with 2.5 g additional leucine or placebo supplementation per
meal.

In part B, 2 groups of healthy elderly will perform a 12 week resistance
training program (3 times/week) combined with nutritional supplementation
provided either immediately or 2 hours after each exercise session.

In both parts, body composition, muscle function and plasma glucose responses
will be compaired before and after intervention.

Part A is a 12 week placebo controlled trial with 7.5 g additional leucine or
placebo supplementation daily (2.5 g/meal).

Part B is a 12 week resistance training program (3 times/week) combined with
nutritional supplementation provided either immediately or 2 hours after each
exercise session.

At the site of the catheter a hematoma could occur. This is the same for the
muscle biopsy. Muscle biopsy is performed by an experienced physician. The
incision made for obtaining the muscle biopsy will heal completely. At the
beginning of the resistance training program, muscle soreness could occur.

An ECG will be performed (rest and exercise) before inclusion to the study
population, to exclude heart failure.

The level of radiation emitted during a DEXA scan is merely a fraction of that
emitted during a regular chest X-ray. The MRI scanner does not apply radiation.
As long as no metals are implanted in the body, there is no danger attached to
MRI scans.

The ingested bolus of glucose is compairable with a commercial sport nutrition
drink. The ingested leucine/proteins are part of the normal diet as a precursor
for protein synthesis and impose no risk.

To minimize the risk for muscle soreness and/or muscle injuries, an experienced
investigator will supervise all training sessions.