Thursday-Abstracts

Thursday, May 30, 2013
S304 Vol. 45 No. 5 Supplement
1553 Board #145 May 30, 2:00 PM - 3:30 PM
Practice Effects of Consecutive administrations of the
sensory Organization Test in healthy College students
Hyung Rock Lee1 , Jessica R. Dysart2 , Michael S. Ferrara2 .
1 2 Murray State University, Murray, KY. The University of
Georgia, Athens, GA.
(No relationships reported)
Postural control is a complex feedback process utilizing multiple sensory-motor
systems, gathering input from the visual, vestibular and somatosensory receptors. The
sensory organization test (SOT) assesses these sensory-motor systems and has been
utilized in concussion management. However, limited research of the SOT has been
conducted to evaluate the practice effect.
PurPOsE: To evaluate the practice effects of four administrations of the SOT within
one day compared to one test on four consecutive days.
METhOds: Twenty-eight healthy college students were divided into two groups;
Group A (10 males, 7 females, age 22.82 ± 5.1 years) and Group B (7 males, 4
females, age 20.27 ± 1.1). Subjects in Group A performed the SOT once a day over
four consecutive days. Subjects in Group B performed the SOT four times in one day
with 20 minute breaks between each SOT. The SOT composite equilibrium score
provided an overall determination of balance performance for each subject. Subcomposite
scores were also calculated for somatosensory, visual, vestibular, and visual
conflict. These scores were analyzed to determine practice effects. Repeated measures
ANOVA was used with statistical significance set at p 0.05). However, the reduction in MVIC was
greater for men (228 ± 18 Nm to 156 ± 18 Nm, 36% decline) than women (147 ± 14
Nm to 114 ± 12 Nm, 22% decline, P < 0.05). Men and women had similar voluntary
activation during control contractions when measured with electrical stimulation over
the muscle (91 ± 3% vs 93 ± 2%, respectively) and with TMS (96 ± 2% vs 94 ± 3%,
respectively). Voluntary activation decreased similarly for men and women after the
dynamic contractions when assessed with electrical stimulation (to 85 ± 3% vs 85 ± 2%,
respectively). Likewise, the increase in superimposed twitch elicited with TMS increased
similarly for men and women (from 1.3 ± 1% to 3.4 ± 1% vs 1.1 ± 1% to 2.6 ±1%).
CONCLusION: Despite similar reductions in power during 6 minutes of dynamic
maximal-velocity knee extension, men exhibited greater fatigue of maximal isometric
force than women. Central and supraspinal fatigue both contributed to the reduction in
MVIC at end-exercise but did not explain the greater fatigue of MVICs exhibited by
men compared with women.
MEDICINE & SCIENCE IN SPORTS & EXERCISE ®
D-31 Free Communication/Poster - Neuroscience
May 30, 2013, 1:00 PM - 6:00 PM
Room: Hall C
1555 Board #147 May 30, 3:30 PM - 5:00 PM
Influence Of Physical Exercise On hippocampal Cb-1
receptor Expression
Ricardo M. Arida, Lívia Blazechi Ferreira, Sérgio Gomes da
Silva, Fabiano Guimarães Novaes Gomes, Alexandre Aparecido
de Almeida, Fulvio Alexandre Scorza, Esper Abrão Cavalheiro.
Universidade Federal de São Paulo, São Paulo, Brazil.
(No relationships reported)
It has been shown that activation of the cannabinoid receptor subtype 1 (CB-1)
modulates neuronal activity and inhibits the release of some neurotransmitters in
the central nervous system. A wide range of neurobiological rewards following
moderate and intense aerobic activity were reported by humans, popularly referred
to the ‘runner’s high’, which may function to encourage habitual aerobic exercise.
Endocannabinoids are endogenous neurotransmitters that appear to play a major role in
generating these rewards by activating cannabinoid receptors as CB-1 in brain reward
regions like hippocampus during and after exercise.
PurPOsE: To investigate the effects of different types and intensities of physical
exercise on the hippocampal expression of CB-1 receptor
METhOds: Animals were submitted to forced or voluntary exercise. To the forced
exercise, Wistar rats were submitted to a program of 5 sessions (acute group) or 30
sessions (chronic group) on a treadmill. For intensive exercise, the speed was gradually
increased to 30 min at 22 m/min; to moderate exercise the speed was gradually
increased to 30 min at 16m/min. For voluntary exercise, each animal was placed in
a box containing a wheel connected to a shaft which has an odometer to measure the
number of turns performed. The animals from chronic and acute groups were divided
into good runners and bad runners, according to the number of turns marked on the
odometer. Their brains were processed for analysis of CB-1 receptor by Western-Blot
technique.
rEsuLTs: A significant increase in the expression of CB-1 receptor was observed in
acute voluntary good runner (1.30) and intensive forced runner (1.26) when compared
to the control group (0.57; p=0.017 and p=0.02 respectively). It was also detected
significant reduction of CB-1 receptor expression in chronic voluntary good runner
(0.35) and intensive forced runner (0.55) compared to control group (1.80; p=0.027
and p=0.035 respectively) and between moderate and intensive forced group (1.51 vs
0.55; p=0.032).
CONCLusION: Our results suggest that an intensive training is necessary to change
the expression of the receptor CB-1 on hippocampus. Thus short term exercise
increased (upregulation) and a long term exercise decreased (downregulation) CB-1
receptor expression.
Suppoted by CAPES, FAPESP and CNPq
1556 Board #148 May 30, 3:30 PM - 5:00 PM
Brain-derived Neurotropic Factor (BdNF) Increases More
in Trained than untrained Females Following acute Exercise
Rick Carter, FACSM 1 , Rachelle Barry 1 , Yunsuk Koh 1 , Allen
Sexton 1 , Jason Fondrick 1 , Dan Chilek 1 , James Williams,
FACSM 2 . 1 Lamar University, Beaumont, TX. 2 Texas State
University, San Marcus, TX.
(No relationships reported)
PurPOsE: To investigate the amplitude and pattern of plasma BDNF concentration
shifts between trained and untrained females, following an acute bout of exercise.
METhOds: Thirteen (7 soccer players; 6 controls) (mean ± SD: age 20.7±1.8 yrs;
height 65.3±2.3 in; weight 147.2±30.5 lbs; BMI 24.2±4.7 kg/m 2 ; waist/hip ratio .7 ±
.1 ) college age women who were free from chronic disease consented to participate
in the study. All subjects completed a cycle ergometry protocol to peak effort with
controls averaging 80% of age, gender specific predicted VO 2peak while soccer players
averaged 138% of predicted. Blood specimens were collected before, immediately
following, and 30 minutes after completing a half hour of cycle exercise at 60% of the
measured VO 2peak .
rEsuLTs: Baseline BDNF (T0) and cortisol values were equivalent (P > .05). A
significant increase in plasma BDNF was noted from baseline to immediately post
exercise (p < .05) with no other statistical differences noted. Trends did appear with
respect to BDNF changes with soccer players maintaining higher values at 30 minutes
of recovery as compared to controls (Plasma BDNF declined 14% in soccer players
and 28% for controls). However, the rate of disappearance did not reach statistical
significance.
CONCLusION: These data confirm that acute moderate to high intensity exercise
elevated plasma BDNF values. Chronically trained females (soccer) had a greater
increase in BDNF as compared to controls with plasma concentrations remaining
ACSM May 28 - June 1, 2013 Indianapolis, Indiana