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Measuring Affective Responses to Different Types of Nature Exposure
Get PDFNatural environments provide many physical and physiological benefits for an individual. Examples may include decreased stress levels, increased intrinsic motivations and prosocial behavior, and more. Fueled by the curiosity of the extent to which nature provides these benefits, this study investigated whether pre-existing preference for either waterscape scenes or mountainous scenes, as well as self-reported affective and associative responses to those environmental exposures are possible explanations for the experience of wellbeing when one is exposed to nature. Measures included the Nature Relatedness Scale, State Vitality Scale, Positive and Negative Affect Scale, and a nature preference scale (mountainous vs. waterscape). Nature relatedness was a significant predictor for state vitality and positive affect, as participants who scored higher on the nature relatedness scale prior to the study rated themselves as happier and more energized after viewing nature scenes. More participants in the water condition cognitively associated themselves interacting with the environment, recounting specific memories of their own, as well as reporting more calm cognitive associations. Also, people who preferred waterscape scenes reported more calm cognitive associations in both conditions. The interaction between picture type and nature preference for the restorative element of fascination showed that individuals who preferred a specific type of nature scene were in turn more fascinated when viewing the scene they preferred. Implications for these results suggest that people who are more closely related to nature experience higher levels of positive affect and state vitality when exposed to natural environments. In addition, one’s own nature preferences result in higher levels of fascination when viewing environments that you like to see
CHANGES IN THE GRADIENT OF FORCE-VELOCITY PROFILES IN SIMULATIONS OF LOADED SQUAT JUMPS CAN BE INDUCED BY INCREASES IN MAXIMUM TORQUE AND RATE OF TORQUE DEVELOPMENT
Get PDFIn multi-segment movements the relationship between the external applied force and the velocity of the whole body or limbs has often been shown to be quasi-linear. It has been proposed that there is an optimal force-velocity profile for an athlete and that deviations from this profile, termed either a ‘force-deficit’ or a ‘velocity-deficit’, can be corrected by training. The aim of this study was to test the hypothesis that alterations in the maximum torque and rate of activation of the torque generator in a two-segment computer model actuated solely by a knee torque generator can explain changes in the gradient of the force-velocity profile during simulations of loaded squat jumps. It was found that an increase in the rate of activation of the torque generator led to a reduction in the gradient of the force-velocity relationship, addressing a velocity-deficit, and an increase in the maximum torque resulted in an increase in the gradient of the force-velocity relationship, addressing a force-deficit. These results provide potential mechanisms by which force-velocity profiles obtained from loaded squat jumps can be altered by training
THE INFLUENCE OF FOOTBALL INFLATION PRESSURE ON IMPACT FORCE AND HEAD ACCELERATIONS DURING FOOTBALL HEADING
Get PDFThe study investigated the effects of ball inflation pressure on head impact biomechanics. In a two-stage study, footballs with a range of ball inflation pressures (0.4 – 0.95 atm) were impacted into a force plate across a range of ball velocities. Next, 12 male players headed a reduced range of inflation pressures (0.4 & 0.54 atm) and ball velocities (5 & 8m/s) whilst instrumented with three-dimensional motion capture markers to assess linear and angular head accelerations. Results suggest that in isolation, a reduced inflation pressure reduces peak impact force across all velocities barring a low velocity of 4.6 m/s. In Vivo, findings suggest that inflation pressure has no effect on linear or angular head accelerations at any velocity, and ball velocity has no effect on linear accelerations. However, a ball velocity of 5 m/s could reduce angular accelerations by 180 rads/s2 (95% CI: 104 – 255 rads/s2)
KNEE KINEMATICS AND KINETICS OF SPORT-SPECIFIC FAKE-AND-CUT MANEUVERS OF VARYING COMPLEXITY IN FEMALE HANDBALL PLAYERS
Get PDFThe purpose of this study was to 1) compare knee joint kinematics and kinetics of fake-and-cut tasks of varying complexity in 51 female handball players and 2) present a case study of one athlete who ruptured her ACL three weeks post data collection. External knee joint moments and knee joint angles in all planes at the instance of the peak external knee abduction moment (KAM) as well as moment and angle time curves were analyzed. Peak KAMs and knee internal rotation moments were substantially higher than published values obtained during simple change-of-direction tasks and, along with flexion angles, differed significantly between the tasks. Introducing a ball reception and a static defender increased joint loads while they partially decreased again when anticipation was lacking. Our results suggest to use game-specific assessments of injury risk while complexity levels do not directly increase knee loading. Extreme values of several risk factors for a post-test injured athlete highlight the need and usefulness of appropriate screenings
GRF ANALYSIS OF TWO ELITE PARALYMPIC SPRINTERS IN STEADY AND RESISTED ACCELERATED TREADMILL RUNNING
Get PDFAnalysis of ground reaction forces (GRFs) allows evaluating performances of paralympic runners with transfemoral amputation. Instrumented treadmills are expensive and low-cost solutions to gather GRFs are worth to be studied. This study aimed to use a commercial treadmill placed on four force platforms to evaluate vertical impulse, braking and propulsive horizontal impulses during steady-speed (SSR) and resisted accelerated (RAR) running. The RAR vertical impulses of the unaffected limb (UL) of the two athletes doubled the values of the affected limb (AL) that has, however, on average 23% larger propulsive action than UL in SSR. The horizontal impulse of AL remains positive in the first 10 steps during RAR, as expected. Agreement between present results and literature confirms that the proposed setup gives sufficient confidence in the evaluation of the sprint technique
QUANTIFICATION OF COORDINATIVE VARIABILITY OF HIP-ANKLE JOINTS FOR SEDENTARY AND ACTIVE YOUNG GROUPS
Get PDFThe aim of the present study was to quantify the variability of joint coordination, during gait, of young sedentary and active at different speeds (preferred walking speed (PWS), 120% of PWS and 80% of PWS) using the previously reported modified Vector Coding technique. Thirty young people participated in this study, of which 15 practiced physical activities at least an hour a day and three times a week, and 15 were sedentary. For data collection they executed a protocol of one-minute walking on a treadmill at each speed, in a randomized order. For the Hip-Ankle joint pair, the coordination was computed during four phases of the gait (first double support, single support, second double support and swing phase), in the sagittal plane. The data were analyzedanalysed using a customized Matlab code. There were no statistical differences for the Hip-Ankle coordination between groups
MODELLING TRANSTIBIAL PROSTHESES FOR SIMULATION
Get PDFInvestigating the effect of a prosthetics size, shape, and stiffness on sports performance requires a theoretical approach, however this requires a more complex representation of the prosthetic beyond those previously adopted. A chain model was used to investigate the level of complexity (n-segments; n=2,3,4) required to reproduce the kinematics and kinetics of a prosthetic during six different movements performed by a unilateral transtibial amputee athlete. The optimal solution was evaluated using an angle-driven simulation model and close agreement (3% RMS difference) was observed between the simulation and recorded performances suggesting the complexity was sufficient. This approach could be employed within theoretical approaches to investigate the cause and effect of prostheses on sporting movements or to custom fit appropriate prostheses for individual athletes
CRITERION VALIDITY OF THE LOWER LIMB ISOKINETIC POWER-FORCE-VELOCITY PROFILING PARAMETERS IN ELITE ATHLETES
Get PDFThe purpose of this study was to investigate the criterion validity of isokinetic leg press Power-Force-velocity (P-F-v) parameters. Forty elite athletes with diverse sporting backgrounds performed a maximal vertical squat jump test and an isokinetic leg press P-F-v profile test. The isokinetic leg press P-F-v profile consisted of leg-extension against 4 given velocity conditions: 0.1, 0.3, 0.7, and 1.2 m/s. Criterion validity was evaluated using correlation between squat jump height and each isokinetic P-F-v parameter (F0, v0, Pmax and, Sfv). Nearly “good” (r \u3e 0.815) correlations were found for Pmax, whereas correlations between the remaining P-F-v parameters ranged from “poor” to “impractical” (r = 0.702– 0.159). This result may fit the previous assumption of P-F-v profiles, that individuals express variable contributions of F0 and v0 for similar Pmax values. Consequently evaluating criterion validity for these parameters (F0 and v0) is likely difficult would be contrary to this P-F-v assumption
PLANTAR FORCE COMPARISONS BETWEEN THE CHASSE STEP AND ONE STEP FOOTWORK DURING TOPSPIN FOREHAND USING STATISTICAL PARAMETRIC MAPPING
Get PDFThe purpose of this study was to investigate the plantar force characteristics of the chasse step and one step footwork during table tennis topspin stroke using one-dimensional statistical parameter mapping (SPM 1d). Twelve national players volunteered to participate in the study. The plantar force of the right foot during the chasse step and one step backward phase (BP) and forward phase (FP) was recorded by instrumented insole systems. Paired sample T tests in SPSS 24.0 (SPSSs Inc, Chicago, IL, USA) were used to analyze peak pressure of each plantar region. For SPM analysis, the plantar force time series curves were marked as a 100% process. A paired-samples T-test in MATLAB was used to analyze differences in plantar force. One step produced a greater plantar force than the chasse step during 6.92-11.22% BP (P=0.039). The chasse step produced a greater plantar force than one step during 53.47-99.01% BP (