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A PRACTICAL OPEN-SOURCE COMPARISON OF DISCRETE AND CONTINUOUS BIOMECHANICAL ANALYSIS TECHNIQUES
Get PDFRecent work has challenged the practice of extracting and analysing discrete summary metrics from continuous biomechanical data. This paper presents a practical comparison of candidate data analysis techniques including frequentist and Bayesian discrete analysis, frequentist and Bayesian statistical parametric mapping, and vector coding. Example 1 compares knee and hip flexion / extension angles during flywheel and barbell squats. Example 2 compares pelvis and thorax transverse rotations during badminton jump smashes by an international and a regional player. All example data and scripts are open-source. Statistical parametric mapping enables comparison of continuous biomechanical variables at time points other than discrete local optima. Combining this approach with vector coding provides information regarding differences in proximal-distal joint coordination throughout a movement. These continuous open-source methodologies can increase the validity and intuitive practical application of biomechanical conclusions
A METHOD COMPARISON OF BLOCK BASED ACCELEROMETERS AND FORCE SENSORS FOR DETERMINATION OF RESPONSE TIMES IN THE SPRINT START
Get PDFThis study compares sprint start response times (RT) derived from load cells in the blocks with a RT from rail mounted accelerometer using methods similar to World Athletics (WA) approved start information systems (SIS). Seven national and international sprinters completed sprint trials that replicated race competition start procedures. Load cells were incorporated into starting blocks and the back block RT were analysed using: visual inspection (Visual RT), a 3SD threshold and CUSUM method, the rail accelerometer RT were analysed using a Visual RT and a 3SD Threshold method. On average the Rail Visual RT was detected 21 ms after the Visual Back Block RT and the Rail 3SD RT detected 27 ms after the Back Block 3SD RT. The results indicated the rail accelerometer detected RT after the back block load cells, highlighting the need for a review of SIS hardware and event detection software
CAN INCREASED MIDSOLE BENDING STIFFNESS OF SPORT SHOES DELAY THE ONSET OF LOWER LIMB JOINT WORK REDISTRIBUTION DURING A PROLONGED RUN?
Get PDFProlonged running has been shown to result in a redistribution of positive lower limb joint work from distal to proximal joints. Running footwear with increased midsole bending stiffness (MBS) has been shown to redistribute lower limb joint work from proximal to distal joints. How increased MBS of running shoes can affect joint work redistribution during a prolonged run, however, is unknown. Therefore, the purpose of this study was to investigate if increasing the MBS of running shoes can delay the onset of positive lower limb joint work redistribution during a prolonged run. Thirteen trained male runners (current 10 km time \u3c 44 min.) performed 10-km runs at 90% of their speed at lactate threshold (sLT) in a control and stiff shoe condition, respectively. Prolonged running resulted in a redistribution of positive lower limb joint work from distal to proximal joints in both shoe conditions. The onset of joint work redistribution, however, was delayed at the metatarsophalangeal and ankle joint when running in the stiff shoe condition. A delayed onset of lower limb joint work redistribution in the stiff condition may result in greater energy stored and returned in distal passive-elastic structures (i.e., Achilles tendon), reducing lower limb muscle work later into the prolonged run. Also, less active muscle volume would be required to perform the same total amount of positive mechanical work when running in the stiff condition because the ankle plantarflexor muscles have less volume than the knee extensor muscles. These results contribute to the notion that footwear with increased MBS likely result in lower metabolic cost, due to delays in distal to proximal lower limb joint work redistribution
FOOTSTRIKE PATTERNS OF HIGH AND MID-MILEAGE NON-REARFOOT RUNNERS DURING AN EXHAUSTIVE RUN
Get PDFThe purpose of this study was to identify the effect of fatigue on footstrike patterns in two groups of habitually non-rearfoot runners. Twenty-eight runners participating in this study were divided into two groups by their weekly mileage. Participants completed a VO2max test to determine the velocity for the fatiguing run. Kinematic, physiological and biochemical data from the beginning and the remaining 3 minutes of fatiguing treadmill run were obtained. The overall time for fatiguing run exceeded 40 minutes (t = 48,1 ± 3,6 min.). The foot angle at the instant of initial contact significantly changed in both groups following fatigue. However, there was significantly less change in the high-mileage group of runners than in the mid-mileage group. The findings of the study suggest that utilizing consistent footstrike pattern in fatigue could probably depend on the fitness level of particular runner
Got Guts?: A Morphological Assessment of Migratory Waterfowl Digestive Anatomy
No full textPhylogeny and diet influence digestive systems morphology. For example, many migratory species experience both hyperphagia and short-term fasting that affects digestive system function and morphology. For most wildlife, the extent to which digestive system morphology varies within a species is relatively unknown. Using migratory waterfowl as an exciting ecological model due to their complex digestive system morphology (e.g., gizzard, small and large intestine, paired ceca), our objective was to evaluate variation in digestive system morphology within and among different species of migratory waterfowl across diverse phylogenies. To achieve our objective, we sampled five species of waterfowl harvested by hunters in the Upper Peninsula of Michigan: ring-necked duck (Aythya collaris), mallard (Anas platyrhynchos), bufflehead (Bucephala albeola), wood duck (Aix sponsa), and green-winged teal (Anas carolinensis), and Canada goose (Branta canadensis). With permission from hunters, we extracted the complete gastrointestinal tract from harvested birds and systematically captured images of the entire gastrointestinal tract. We used ImageJ software to measure the gastrointestinal tract of each animal and ANOVA analysis to determine whether differences in digestive system morphologies were statistically significant. Our results indicate that variation among species was greatest when comparing the distance from the crop to the paired ceca and between the two ceca. No significant variation in morphology was observed between sex within any species We hope our work motivates other researcher to engage the hunting community in efforts to advance our understanding of variation in wildlife digestive system morphologies, generating new insights into the natural history of diverse species
Examining mental illness in John Green’s Turtles All the Way Down: OCD- More than just attention to detail
No full textEFFECT OF SPRING CANE TIPS ON MEASURES OF PEAK VERTICAL GROUND REACTION FORCES DURING WALKING
Get PDFThis study examined the effect of different spring cane tips on measures of peak vertical ground reaction forces (GRFs) transferred to the cane and foot during walking. Thirty-three participants were fitted with a T-Scope Knee Brace® to simulate a knee flexion contracture. Participants performed cane-aided walking tests under four different spring cane conditions. Each participant walked five trials for each cane tip over two force plates to measure GRFs for the cane and foot respectively. Four (spring cane tip conditions) x two (cane and foot) repeated measures ANOVA was conducted on measures of vertical GRFs. This analysis revealed a significant main effect on measures of vertical GRFs between the cane and foot, F(1,32) = 225.79,p \u3c .05, η2 = .876. This outcome has implications for cane tip designs to prevent upper extremity injuries occurring due to cane use
TECHNIQUE SELECTION DURING LANDINGS IN ARTISTIC GYMNASTICS
Get PDFThis study aimed to quantify the mechanical characteristics of two landing techniques performed by artistic gymnasts. Seven senior female artistic gymnasts performed 20 drop landings with different foot positions: feet together (women’s technique) or hip width apart (men’s technique). Synchronised 3D kinematic (250 Hz) and kinetic data (1000 Hz) were collected for each trial and biomechanical variables associated with lower extremity injury during landing were analysed. Significant differences (α \u3c 0.05) in ankle dorsiflexion and inversion at peak vertical ground reaction force (FPeakZ) were identified between techniques. The findings suggest the female landing style to be associated with increased FPeakZ, loading rate and reduced knee flexion. Whereas the male landing style was reported to exhibit significantly increased ankle inversion angles and reduced ankle dorsiflexion angles at FPeakZ. Results suggest that both strategies present characteristics associated with increased risk of differing injuries
THE BIOMECHANICAL EFFECTS OF ROTATOR CUFF TAPING ON MUSCLE ACTIVITY AND THROWING VELOCITY IN BASEBALL PLAYERS
Get PDFThe purpose of this pilot study was to investigate the effect of taping (Kinesio tape, placebo tape, no tape) on the velocity of an overhead baseball throw and muscle activity using surface electromyography (EMG) and a radar gun in a population of baseball players. Participants (n=13) completed three maximal overhead throws while surface EMG and velocity of overhead throws was recorded. There was a statistically significant two-way interaction between tape and muscle type, F(6,66) = 2.656, p \u3c .05. There was no statistically significant difference in throwing velocity with the application of the different taping conditions
EFFECTS OF FATIGUE ON KINEMATICS AND SHOCK ATTENUATION DURING DOWNHILL TRAIL RUNNING
Get PDFThis study assessed the effects of a competitive trail run on running kinematics and shock attenuation in well-trained trail runners. Nine male runners performed a simulated short trail running race. Prior and 5-min after the race, participants completed a 290-m downhill run at pre-determined preferred speed. Inertial measurement units were used to assessselected kinematic parameters. The contact time showed a moderate increase in the fatigued condition (pre: 0.215 (0.024) s vs. post: 0.226 (0.219) s; p2vs. post: 49.1 (11.9) m/s2; p=0.038; d=0.56), while peak tibial acceleration and shock attenuation showed no change (p\u3e0.05). These findings confirm that running-induced fatigue impacts running kinematics, although shock attenuation was unaltered with the present fatiguing protocol.
This study assessed the effects of a competitive trail run on running kinematics and shock attenuation in well-trained trail runners. Nine male runners performed a simulated short trail running race. Prior and 5-min after the race, participants completed a 290-m downhill run at pre-determined preferred speed. Inertial measurement units were used to assessselected kinematic parameters. The contact time showed a moderate increase in the fatigued condition (pre: 0.215 (0.024) s vs. post: 0.226 (0.219) s; p2vs. post: 49.1 (11.9) m/s2; p=0.038; d=0.56), while peak tibial acceleration and shock attenuation showed no change (p\u3e0.05). These findings confirm that running-induced fatigue impacts running kinematics, although shock attenuation was unaltered with the present fatiguing protocol