Much of the differences between strength (S) and endurance (E) exercise can be attributed to the
contrasting endocrinological and molecular responses between the two exercise modes. From the
current literature, it seems that aortic arterial stiffness, a reliable cardiovascular mortality predictor,
also
responds
differently
to these two modes of exercise. It is thus important to understand
the acute responses that combined exercise loads may invoke, as acute responses are known to
drive chronic adaptations. Furthermore, testosterone has been cited as a key hormone in cardiovascular
protection
and
its
effects
may
mediate
blood
flow
and
hemodynamics.
Currently,
there
are
very
few
studies
investigating
combined exercise loadings and its effect on central hemodynamic
and endocrine response. Therefore, the purpose of the study was to determine the acute
arterial stiffness and testosterone response to different concurrent strength and endurance models
of
exercises. In addition, the recovery profile from these loadings will also be elucidated to gain
a better understanding of its time course.
A group of eight male (33.5 ± 5.9 years) recreationally endurance trained participants took part
in the study. All participants took part in three loading sessions; one with S loading followed
immediately by E loading (S+E), vice versa (E+S), and integrated (INT), where E and S alternated
during the session. Participants were tested for their E (maximal oxygen consumption;
VO
2MAX
) and S performance (maximal bilateral dynamic leg press, 1RM) and performed all
loadings in a randomized order. S primarily focused on leg extensor muscles including both
maximal and explosive exercises (2 x 10 reps squat jumps, drop jumps, bounding and 3 x 10 reps
leg press with 80% of 1 RM with 2min rest between the sets) and E was performed as continuous
running with intensity between 80 – 85% VO
2MAX
. Pulse wave velocity (PWV) and blood pressure
values were determined pre (PRE), post (POST) and 30 minutes after (POST30). Serum
testosterone concentrations, maximum voluntary contraction (MVC) and rapid force production
(RFP) were determined for PRE and POST loadings and repeated after recovery of 24h and 48h.
The main findings were significant decreases in mean PWV PRE to POST (7.9 ± 0.7 m/s vs 7.3
± 0.8 m/s, respectively) (p = 0.017) for combined exercise loadings and mean SBP POST to
POST30min (128.0 ± 5.1 vs 134.6 ± 5.9 mmHg, respectively) (p = 0.032). Mean DBP had a statistically
significant interaction effect between time and loading (F(4, 28) = 3.677, p = 0.016).
There was a statistically significant reduction in MVC from PRE to POST (3291 ± 1007 N vs
2888 ± 804 N) (p = 0.037), as well as in RFP from PRE to POST (2182 ± 294 vs 1917 ± 239 N)
(p = 0.005). In summary, the present results showed that an order effect may exist, when SBP
and DBP are taken together into consideration with PWV. Combined exercise did not lead to
detrimental effects in PWV and the ES order had the larger response. Additionally, INT showed
the least amount of force production deficit among all three orders. These findings may be useful
in assisting the exercise prescription in elderly, hypertensive and pre-hypertensive populations.
...
