The impact of jumping exercise and collagen supplementation on bone turnover markers in healthy males

Bone health is a critical factor for athletes as bones provide the levers for
muscles to move the joints, and strong bones decrease the risk of bone
fractures. Particularly cyclist can benefit from exercise and nutrition
interventions to stimulate bone health, as this population is characterized by
an impaired bone mineral density. Jumping exercise has been identified as a
feasible and effective exercise intervention to stimulate collagen synthesis
and increase BMD. However, there is considerable debate on the optimal volume
and frequency of jumping exercise to maximize bone collagen synthesis.
Furthermore, preliminary evidence suggests that collagen supplementation may
also stimulate bone collagen synthesis. It is currently unknown whether
collagen supplementation can augment the increase in bone collagen synthesis
after jumping exercise.
There is evidence to suggests that cycling exercise training has a negative
effect on bone metabolism. Hence, it may me of particular interest for elite
cyclists to know whether jumping exercise and collagen supplementation can
counteract the deleterious effects of cycling exercise training on bone tissue.

The main objective of the current project is to assess the effect of jumping
exercise combined with collagen supplementation on bone turnover. This will be
investigated by means of two sub-studies.
Sub-study 1a: To examine the effect of collagen supplementation and jumping
exercise on bone turnover markers in healthy males.
Sub-study 1b: To examine the effect of collagen supplementation and jumping
exercise on bone turnover markers after a cycling exercise bout in trained
cyclists.

Randomized, cross-over intervention studies

Study 1a: for 3 days, volunteers will consume either a collagen protein
supplement (20 g; 1 or 2 x p/d) or an isocaloric placebo supplement
(maltodextrin; 1 x p/d), additional to their habitual diet, combined with a 5
minute jumping exercise session. Study 1b: for 2 days, volunteers will consume
either a collagen protein supplement (20 g; 2 x p/d), additional to their
habitual diet, combined with a 5 minute jumping session or no intervention.

Participants will visit our lab 5 (study 1a) and 4 (study 1b) times. Overall,
26 (1a) and 16 (1b) blood samples (10 mL/sample) will be drawn (via an
intravenous canula or vena punction). The discomfort of this procedure is
transient and is comparable to having an injection by a needle, or donating
blood.
Participants will have to perform non-exhaustive rope skipping exercise, which
is meant to stimulate bone synthesis.
Test products (collagen) are commercially available, food-grade food
ingredients that are safe in the amounts consumed in this study.
Body composition will be assessed once by DXA. The measurement is painless,
non-invasive and involves only low radiation exposure (<10 *Sv).
Two food dairies will be collected in the week before the first trial to assess
baseline dietary intake. Three (2 in study 1b) food diaries will be collected
during the 3-day (2-day study 1b) intervention period of the first trial, for
use of diet quantity replication during trial 2 and 3 (for study 1a only) .
Volunteers have to perform a 2 h moderate intensity cycling exercise bout (1b
only).
Participants will perform an exercise tests to determine VO2max. Although the
exercise test can be considered as strenuous exercise, the burden is limited to
temporary discomfort and muscle soreness (1b only)

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