european college of sport science

OP-SM03 Sports Medicine 3
DISCUSSION: The results of this study showed that vigorous but relatively short late-night exercise performed 2-2.5 hours before bed time
affects cardiac autonomic control especially during the first hours of sleep. However, objective and subjective sleep quality may be even
enhanced after exercise compared to control condition. We conclude that this kind of exercise procedure has minor effects on the essential
recovery process during sleep.
ROLE OF STRENGTH TRAINING IN ENDURANCE RUNNERS DURING PREPARATORY, MAXIMAL VERSUS EXPLOSIVE,
AND REDUCED STRENGTH TRAINING PERIODS.
TAIPALE, R.S., GITONGA, D., WALKER, S., NUMMELA, A., VESTERINEN, V., MIKKOLA, J., HÄKKINEN, K.
UNIVERSITY OF JYVÄSKYLÄ, KIHU-RESEARCH INSTITUTE FOR OLYMPIC SPORTS
Strength (STR) and endurance (END) training produce divergent adaptations and are often performed concurrently. An interference effect
(1) between STR and END training is often related to high intensity/volume and long duration of training, but it is possible for concurrent
training to lead to increased STR and END performances even in endurance athletes (2). A reduction in training stimulus leads to a reversal
in adaptations as demonstrated by decreased activation and STR of detrained muscles (3).
Twenty-eight male recreational END runners (mean±SD, age 35.4±6.8yrs, height 180±5.3cm, body mass 79.3±7.5kg) were divided into
three STR training groups: maximal (M=11), explosive (E=10) and circuit training (C=7). Within these groups, subjects completed 6 weeks of
common preparatory STR training (PRE) and then a specific 8-week STR training intervention (STI) followed by 14 weeks of intentionally
reduced strength training and increased endurance training (RST). STR training (including at least two exercises for leg extensors) occurred
on average 1.3±.02, 1.5±.03 and 0.5±.03 times per week in each training period, respectively, while END training volume (running
km) increased progressively throughout the study. Concentric leg press strength (1RM), jumping power (CMJ), muscle activation (EMG of VL
+ VM) and END performance (vVO2, VO2MAX, running economy (RE)) were measured prior to PRE (-6), at 0, 4 and 8 weeks of STI and
after RST (+14).
During PRE and STI, 1RM improved significantly in all groups peaking at 4 (7.7, 3.2 and 6.4% in M, E and C from -6, respectively), while
significant gains in CMJ peaked at 8. Gains in 1RM were accompanied by increased EMG of VL+VM in M and E (p=0.027 and 0.002) but
not in C. VO2max increased only in M from -6 to 8 (4.3%), vVO2 improved significantly in all groups from -6 to 8 and RE in E improved
significantly by 2.4%. Following RST, progressive decreases were observed in 1RM, CMJ and EMG which were significant in 1RM and EMG
of M (p=0.002 and 0.038). However, significant increases in vVO2 of M and E (4.7 and 2.4%), RE of M (7.7%) as well as some gains (n.s.) in
VO2max continued in M and E.
Both M and E STR training performed concurrently with high volume END training led to increases in 1RM, CMJ and EMG but strength
development plateaued indicating some interference over a prolonged period. Nevertheless, these neuromuscular improvements were
accompanied by progressive gains in VO2max, vVO2 and RE. RST resulted in decreases in 1RM, CMJ and EMG; however, vVO2 and RE
continued to improve in M and E. Adaptations to ST were maintained to some extent, since 1RM, CMJ and EMG did not fall below starting
values. Thus, improved neuromuscular performance and increased preparedness for an increase in running volume due to STR enabled
subjects to improve END performance.
1. Hickson RC Eur J Appl Physiol. 45: 255-263, 1980.
2. Mikkola J et al. J Strength Cond Res. 21:613-620, 2007.
3. Häkkinen K Crit Rev Phys Rehab Med. 6:161-198, 1994.
10:15 - 11:45
Oral presentations
OP-SM03 Sports Medicine 3
EFFECT OF NSAID ON HUMAN SKELETAL MUSCLE SATELLITE CELLS FOLLOWING ECCENTRIC EXERCISE
MIKKELSEN, U.R., MACKEY, A.L., HELMARK, I.C., SKOVGAARD, D., KJÆR, M., LANGBERG, H.L.
INSTITUTE OF SPORTS MEDICINE COPENHAGEN, BISPEBJERG HOSPITAL, DK-2400 COPENHAGEN NV, DENMARK
Introduction: Satellite cells – the stem cells of skeletal muscle – are essential for skeletal muscle adaptation to exercise and for muscle
regeneration. They contribute to hypertrophy by providing new myonuclei and assist in repair of damaged muscle fibre segments. Nonsteroidal
anti-inflammatory drugs (NSAIDs) are widely consumed by athletes when faced with injuries and by rheumatic patients, but the
influence of these drugs on muscle satellite cells and adaptation is not fully understood. Following a 36 km run the observed increase in
satellite cell number (27%) was blunted by ingestion of NSAIDs (Mackey et al., 2007) pointing towards a negative influence of NSAIDs on
satellite cell proliferation in vivo in humans. The aim of the present study was to investigate the effect of local NSAID infusion on satellite
cells in vivo in human muscle.
Materials/Methods: Eight healthy male subjects (unaccustomed to leg resistance exercise) performed 200 maximal eccentric contractions
with each leg. NSAID (Indomethacin) was infused via a microdialysis catheter into one leg (NSAID leg) before, during and for 5 hrs after
exercise, the other leg being working control (unblocked leg). Biopsies were sampled from m.vastus lateralis before and 8 days post
exercise. Satellite cells were analyzed by immunohistochemistry using antibodies against the transcription factor Pax7, and neural cell
adhesion molecule (NCAM). Cell proliferation was analyzed using an antibody against the cell cycle marker Ki67.
Results: The number of Pax7+ cells per myofibre was increased by 75 % on day 8 post exercise in the unblocked leg (mean 0.13, SE 0.03)
compared with pre exercise (mean 0.08, SE 0.02, P=0.03), while levels were unchanged in the NSAID leg (mean 0.06, SE 0.01, P=1.0). On
day 8 post exercise the number of Pax7+ cells (per myofibre) tended to be lower (P=0.06) in the NSAID leg compared to the unblocked
leg.
Very few proliferating (Ki67+) cells were found with no effect of NSAID, on average only one Ki67+ cell was found per 100 myofibres on
day 8 post exercise.
Conclusion: The results indicate that NSAIDs may negatively affect satellite cells and muscle adaptation following eccentric exercise. This
is clinically relevant given the widespread consumption of NSAIDs among athletes and rheumatic patients.
526 14 TH
ANNUAL CONGRESS OF THE EUROPEAN COLLEGE OF SPORT SCIENCE