The primary aim of the current research project is to explore whether nutritional supplementation and resistance training might be combined to produce synergistic effects in the prevention of muscle loss during aging.

A secondary aim of this project is to investigate the effects of carnitine with leucine supplementation, in comparison to carnitine supplementation alone, on muscle strength and body composition.

The hypothesis is that resistance training combined with nutritional supplementation have a more beneficial effect than resistance training alone in the prevention of muscle loss during aging. Leucine stimulates carnitine transport into the muscle cells, which improve mitochondrial capacity. Modification in energetic of skeletal muscle affects the body composition and muscle performance.

The study will be included volunteers - women between 60 - 72 years old (n=60). The patients are randomly assigned to two experimental groups (n=20) and control group (n=20). During the 24-weeks intervention period, Group A undergoes training procedure supplemented with the carnitine and leucine, whilst group B undergoes training procedure supplemented with leucine. At the same time control group go through only training procedure. Measurements are performed before, at the mid-point, and at the end of the intervention period.

Approximately 1 week prior to the experimental trial day, participants perform a familiarization session during which one-repetition maximum (1RM) strength testing is also performed to determine the experimental exercise load. Resistance exercise training is performed twice weekly on non-consecutive days (Monday+Thursday, or Tuesday+Friday) for 24-weeks under direct supervision by a research assistant. Prior to a training session subjects are required to perform warm - up on the treadmill (walk) and static stretching, after each session - cool down on the cycle ergometer and static stretching. Resistance exercise for each session consisted of 6 exercises: horizontal seated leg press, seated chest press, leg extension, shoulder press, lat pull-down seated row, seated cable row First two weeks of training consist of 3 sets of 10-12 repetitions and are keeping exercises at 65% of 1 repetition maximum (1RM). After this period training consists of 3 sets of 6-8 repetitions and is progressing to 80% of 1RM. The 1RM is re-evaluated every 2 weeks, and the training load is adjusted accordingly. The exercise program follows the recommended guidelines for older adults by the American College of Sports Medicine and the National Strength and Conditioning Association.

Inclusion Criteria:

• aged-matched, no chronic disease, doctor's note about the lack of restrictions to perform resistance exercises

Exclusion Criteria:

• diabetes, liver, heart and renal diseases, gastric problems, as well as using the vitamin supplements