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Results 58 participants (72%) completed primary outcome follow-up assessments. The intervention group significantly improved compared to the control group for PTSD symptoms, (mean difference = 5.39, 95% CI 0.26 to 10.52, p=0.04), however, the significant betweengroup difference was lost when missing data were imputed. There were significant between-group differences on the secondary outcomes at follow-up: depression (N=51) (mean difference= 17.44, 95% CI 5.95 to 28.93, p=0.004), waist circumference (N=37) (mean difference = 3.56, 95% CI 0.17 to 6.95, p=0.04) and sleep quality (N=55) (PSQIA) (mean difference = 2.46 95% CI 0.07 to 4.86, p=0.04).
Mean adherence was 7 supervised sessions (range 1-11). Discussion This study provides preliminary evidence that exercise may be effective in reducing both PTSD and depressive symptoms, as well as improving body composition and sleep quality in PTSD patients.
High proportion of participant loss-to-follow-up is a limitation of this study. This trial has important clinical implications and supports the inclusion of exercise programs within PTSD treatment facilities. References Boscarino, J. A. (2004). Ann NY Acad Sci, 1032, 141-153. de Assis et al (2008). Clinics (Brazil), 63(4), 473-478.
CONCENTRIC AND ECCENTRIC TORQUE IN COPD PATIENTS VS. HEALTHY CONTROLRinaldo, N., Coratella, G., Lanza, M., Schena, F.
University of Verona Introduction Presence of muscle wasting is common in Chronic Obstructive Pulmonary Disease (COPD) patients across all disease stages (Seymour J.M., 2010) but eccentric (ECC) contraction results greater compared to healthy control (HC) subjects (Mathur S., 2007). The aim of our study is to outline a description of COPD strength performances as a function of contraction modalities and velocities. Methods Thirtyfive COPD males (mean FEV1=64.76±20.08% of predicted; FEV1/FVC= 57.35±13.56% of predicted; age 67.21±4.7 years) and 25 HC males (FEV1= 115.06±17.43% of predicted; FEV1/FVC=101.87±6.62% of predicted; age 65.15±5.69 years) performed isokinetic knee extensors concentric (CONC) and ECC torque at 30 and 210 deg/s. Vastus lateralis muscle architecture, 6MWT and 1RM Leg press were performed.
One way ANOVA and Pearson coefficient were used to detect significant differences between groups and correlation between variables.
Results HC was significantly better in FEV1 (p0.001), FEV1/FVC (p0.001), 6MWT (p0.001) and 1RM Leg press (p0.05). Only CONC 30deg/s peak torque was significantly higher in HC compared to COPD (p0.05). No differences resulted in muscle architecture, fast CONC and ECC torque. Significant differences between groups ECC/CONC peak torque ratio (30 deg/sec p0.001; 210 deg/sec p0.01).
Significant correlations were found between FEV1 and 6MWT (0.719 p0.001), 1RM Leg press (0.449 p0.001), peak torque contraction at 30 deg/sec (0.427 p0.01; 0.280 p0.05), at 210 deg/sec (0.285 p0.05; 0.276 p0.05) and ECC/CONC peak torque ratio at both velocities (-0.562 p0.001; -0.292 p0.05). Same results were observed between FEV1/FVC and parameters assessed. Discussion COPD patients showed lower health related parameters and performed lower CONC contraction compared to healthy controls. Interestingly, COPD preserved ECC contractions and fast CONC torque. ECC contraction seems to involve fast twitch motor units (Duchateau J., 2008) and COPD hypoxia leads fiber shift towards IIx fibers (Gosker H.R., 2002). Therefore, COPD males seem to develop favorable profile to minimize strength loss likely due to neural-muscular modification. References Mathur S. et al. Preservation of eccentric torque of the knee extensors and flexors in patients with COPD; J Cardiopulm Rehabil Prev. 2007; 27:411–6; Duchateau J. et al. Neural control of shortening and lengthening contractions: influence of task constraints; Physiol. 2008; 586:5853-64; Gosker H.R. et al. Skeletal Muscle fibre-type shifting and metabolic profile in patients with chronic obstructive pulmonary disease. Eur Respir J. 2002; 19:617-25. Seymour J.M. et al.
The prevalence of quadriceps weakness in COPD and relationship with disease severity; Eur Respi J. 2010; 36: 81-88.
CHANGES IN WALKING STEPS DURING PREGNANCY. A MULTI-ETHNIC POPULATION-BASED STUDYRichardsen, K.R.1, Jenum, A.K.1,2, Moerkrid, K.2,3, Sletner, L.2,3, Birkeland, K.I.2,3, Berntsen, S.4 Norwegian resource centre for women's health |Department for women's- and children's heal2 Faculty of Medicine; University of Oslo 3 Dep. of Endocrinology, Obesity and Preventive Medicine; Oslo Univer Introduction: Pregnant women without medical contraindications are recommended to spend 30 minutes or more in moderate to vigorous intensity physical activity (PA) on most, if not all days of the week. However, most epidemiological research typically employ subjective reports of PA. The aims of the present study are (1) to describe PA change operationalised as objectively recorded daily steps in early
gestation and gestational week (GW) 28, and, (2) to investigate the association between core set variables and steps in GW 28. Methods:
Prospective data from a multi-ethnic cohort from Oslo/Norway (n=823) of pregnant women consisting of 40.8% from Western countries, 24.3% from South Asia, 15.3% from Middle East and 19.6% from other countries. Steps were recorded by the activity monitor SenseWear™ Pro3 Armband in early gestation ( 20 weeks) and in GW 28. Covariates in multiple linear regression analysis were steps in early gestation, BMI, pregnancy-induced emesis, subjective health, ethnicity, education, occupation, age and parity, while steps in GW 28 was the dependent variable. Results: Step data from 528 women with valid recordings from both visits were analysed. The ethnic group mean values for daily steps in early gestation ranged from 7183 to 9185, and Western women walked significantly more steps compared to all other ethnic groups (p0.001). The percentage drop from early gestation to GW 28 ranged from 4.1% to 9.0%, and it was most pronounced for women from other countries and Western countries. In absolute terms, significant reductions were only seen in women from other countries (p=0.02) and Western countries (p0.000). Ethnicity (p=0.01), occupation (p=0.04) and parity (p=0.03) were all significantly associated with steps at GW 28 but not after adjusting for steps in early gestation. Steps in early gestation explained 33% of the variance in steps at GW 28 (coefficient with 95% confidence intervals; 0.56 (0.49, 0.63) steps (p0.001)). Discussion: Steps dropped markedly between early gestation and GW 28 across ethnic groups. Steps in early gestation was an important predictor for steps in GW 28, also after adjusting for other covariates, such as subjective health. Women with few steps in early gestation are at risk for low PA throughout pregnancy and interventions to promote PA in pregnancy should be tailored to their needs.
08:30 - 10:00 Oral presentations OP-BN07 Biomechanics [BM] 7
UNSTEADY HYDRODYNAMIC FORCES ACTING ON A ROBOTIC HAND AND ITS FLOW FIELDTakenoya, F.1,2, Hirako, T.2, Ota, E.2, Kageyama, H.3, Yamamoto, N.4, Ryushi, T.5, Shioda, S.2 University of Tsukuba, 1:Hoshi Uni. 2: Showa Univ. 3: Kiryu Univ. 4: Japanese Red Cross Hokkaido College. 5: Daito Bunka Unvi.
Introduction Although an unsteadiness in the flow field during swimming must be considered (Matsuuchi et al. 2009), a quasi-static approach using the coefficients of drag and lift obtained under steady flow conditions has been the mainstream scientific method to predict fluid forces. Therefore, we attempted to directly measure the hydrodynamic forces, the pressure distribution, and the flow field around a hand by using a robotic arm and PIV. The advantages of using a robotic arm are that the obtained data are highly reproducible and that the experimental parameters (e.g., angle of attack and velocity of the hand) are computer controllable. At the first stage, we selected relatively simple hand motions to investigate systematically the effects of angle of attack, relative velocity, and acceleration for generating hydrodynamic force. By investigating the interactions among these data, we aimed to clarify the mechanism of generating unsteady force during swimming. Methods The robotic arm consisted of the trunk, shoulder, upper arm, forearm, and hand, and it was independently computer controllable in five degrees of freedom. The robotic arm was fixed above the flume with a two-dimensional (2D) load cell (LSM-B-SA1 Kyowa). The elbow-joint angle of the robotic arm was fixed at 90°, and the arm was moved in semicircles around the shoulder joint, perpendicular to the water surface. Two-component PIV was used for flow visualization around the hand. Eight pressure sensors (PS-05KC KYOWA) embedded in the hand model to measure the pressure distribution on its surface. The data of the forces by the load cell and pressure acting on the hand by the pressure sensors were sampled at 200 Hz and stored on a PC. Results and Discussion When the maximum resultant force acting on the hand was observed, a pair of counter-rotating vortices appeared on the dorsal surface of the hand. A vortex attached to the hand increased the flow velocity, which led to decreased surface pressure, increasing the hydrodynamic forces. This phenomenon is known as the unsteady mechanism of force generation (Dickinson and Gotz, 1993). We found that drag force was 72% greater and that lift force was 4.8 times greater than values estimated under steady flow conditions.
Measurement of a flow field has revealed that the behavior of certain kinds of vortices generated by unsteady hand movement plays an essential role in generating high hydrodynamic force. It is presumable that swimmers receive the benefits of this unsteady hydrodynamic force. Further studies are necessary to consider and analyze data obtained in realistic situations and reproducible by the robotic arm. In this way, a real swimming stroke pattern can be analyzed, making it possible to confirm the most efficient stroke technique. References Matsuuchi, K., Miwa, T., Nomura, T., Sakakibara, J., Shintani, H., Ungerechts, B.E., (2009). Journal of Biomechanics 42, 42-47. Dickinson, M.H., Gotz, K.G., (1993). Journal of Experimental Biology 174, 45-64.