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Official Journal of the American College of Sports Medicine flexion followed by the RF muscle activity. The delay of VI activity was too long in terms of the spinal reflex. The VI activation may be elicited by afferent input from the sensory receptors in the knee joint via supraspinal pathway. 1549 Board #141 May 30, 2:00 PM - 3:30 PM Power and strength Training on Functionality and Maximal Isometric Contractions in Elderly Paula B. Lopes1 , Paulo C. Bento1 , Gleber Pereira2 , Jean F. Cavazza1 , Renata Wolf1 , André F. Rodacki1 . 1Federal University of Paraná, Curitiba, Brazil. 2Positivo University, Curitiba, Brazil. (No relationships reported) It has been proposed that the ability to generate force quickly (power) is more effective than the ability to produce large amounts of force (peak force) (MARSH et al., 2009), which are relevant aspects to reduce the risk of falls (MELZER et al., 2009). Studies involving strength and power training have presented conflicting results on functional ability, torque and rate o force development. PurPOsE:To compare the effects of power and strength training on the functional capacity, torque and rate of torque development of the elderly. METhOds:Thirty-seven elderly women (above 60 years) were divided into 3 groups: control group (CG; n=11), power (PT; n=12) and strength (ST; n=14) training. Participants were invited to perform four functional tests: 6 minutes walking, seat and reach test, seat to stand and the foot up and go test (RIKLI & JONES, 1999). The ability to produce maximal voluntary isometric contractions (peak and rate of torque development) was determined using a maximal voluntary isometric contraction test applied to the extensor and flexor muscles of the hip, knee and ankle joints. The PT and ST groups underwent a 12-wk training period and all groups were requested not to engage in any other physical activity program during the study or to change their physical activity routines. A one-way ANOVA was used to compare the results between the groups (p
<strong>Thursday</strong>, 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
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