The Effect of Creatine Supplementation on Muscle Loss During Immobilisation

Muscle loss can occur for several reasons, such as inactivity because of
illness or injury, illnesses themselves or simply old age. A decrease in muscle
mass can have a profound impact on quality of life, as it can lead to decreased
strength, insulin resistance, lower basal metabolic rate and obesity. One way
to induce muscle loss and study its effects is immobilisation. Previous studies
have shown that immobilisation of the knee can rapidly induce muscle atrophy.
To reduce rehabilitation time following immobilization intervention strategies
need to be developed to reduce the loss of muscle during immobilisation.
Several nutrients have shown promise regarding the protection of muscle mass in
catabolic situations, one of which is creatine. With this study we investigate
whether ingesting creatine monohydrate during immobilization will reduce the
loss of muscle during a 7 days sinlge leg immobilisation period.

The primary aim of this study is to determine the effect of creatine
supplementation on muscle mass loss during short-term immobilisation in
healthy, young people. In addition, we aim to study the underlying mechanisms
of creatine and disuse muscular atrophy.

The present study will use a randomised, double-blind, placebo-controlled
parallel-arm study design with two groups. All volunteers (n=30) will be
subjected to 7 days of one legged knee immobilisation by means of a full leg
cast, either with (n=15, creatine group) or without (n=15, control group)
creatine monohydrate supplementation. The creatine group will be loaded for 5
days prior to immobilisation by providing 20 g of creatine per day. This will
ensure that muscular creatine stores are at maximal capacity before the leg is
immobilised (13, 26, 27). After the loading phase creatine monohydrate dosage
will be reduced to a maintenance dose of 5 g per day, which will be taken
during immobilisation and during the recovery week after the immobilisation.

One leg will be immobilized at a 30 degree knee joint angle of flexion for 7
days by means of a full leg cast.
In addition, participants will ad random be allocated to the creatine group or
placebo group. In the week before the 7 day immobilisation periode participants
in the creatine group will receive 20 g creatine monohydrate per day. During
the immobilisation period and post-immobilisation period the participants in
the creatine group will receive 5 g of creatine monohydrate per day. In
contrast during the 3 week intervention period, participants in the placebo
group will receive a placebo.

The risks involved in participating in this experiment are minimal.

The incision made for obtaining the muscle biopsy will be performed by an
experienced physician and will heal completely. Within our research group we
have extensive experience with taking muscle biopsies. During the blood draw
there is a small risk of fainting or haematoma. These risks are minimized by
using trained and experienced personnel for taking the blood draw and always
applying adequate pressure following the blood draw.

The Aviko vacuum-packed and pre-weighed meals are normal food products and have
been cleared for human consumption. There are no complications associated with
the procedure of a single slice lower limb CT scan.

The immobilization periode will lead to loss of muscle mass and strength in the
immobilized leg. However, previous studies have shown that this loss in muscle
mass and strength returns to pre-immobilized values within weeks after cast
ermoval, without specific training.