ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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LOWER LIMB MUSCLE RECRUITMENT STRATEGIES DIFFER BETWEEN ELITE AND RECREATIONAL ICE HOCKEY PLAYERS
Full text linkUnderstanding the muscle recruitment strategies that have the largest contribution to performance is essential in sports biomechanics. The aims of this study were to characterise principal muscle activation patterns during accelerative hockey skating and to classify skill levels of players based on their principal muscle activation patterns. Key features of lower limb muscle activation strategies during accelerative skating were extracted and used to classify, with 83% success, elite and recreational players’ acceleration strides. Classification and functional interpretation of muscle coordination is important to understand the differences in muscle recruitment strategies across skill levels, and to monitor changes that result from training
EVALUATION OF ELBOW AND FOREARM MOTION BETWEEN SIDEARM AND OVERHAND PITCHING
Full text linkThis study is to analyze the differences in kinematics, electromyography (EMG) and ultrasonography between two types of pitchers. We intend to observe and simulate the muscles around glenohumeral and elbow joints in different pitching motions and hope to discover the connections and differences in between. 12 pitchers from the top level were recruited. Larger elbow flexion was found in sidearm pitchers during the acceleration phase. Decrease of the distance of nerve to medial epicondyle was also found as the elbow moved to a more flexed position. More anterior translation of the ulnar nerve might occur during acceleration phase. Slightly lower flexor carpi radialis (FCR) activity was displayed in sidearm pitchers, showing that FCR might play a less crucial role in protecting medial elbow by providing less varus torque
ELECTROMYOGRAPHIC INTRA INDIVIDUAL VARIABILITY IN FRONT CRAWL SWIMMING
Full text linkThe purpose of this study was to assess the intra-individual variability of two bilaterally measured EMG signals (deltoideus medialis and rectus abdominis) in front crawl swimming and compare the influence of the normalization technique on several variability measures. Fifteen well-trained adult male competitive swimmers were tested and four additional measures of variability besides mean and standard deviation were calculated. The repeatability of swimming movements was high for both tested muscles and one stroke cycle might be sufficient to determine a swimmers movement pattern. Variance ratio was suggested as a preferred additional measure of variability as it was least susceptible to differences in normalization method
HAMSTRING STIFFNESS IS RELATED TO ANTERIOR TIBIAL TRANSLATION WHEN TRANSITIONING FROM NON-WEIGHT BEARING TO WEIGHT BEARING
Full text linkAnterior tibial translation (ATT) loads the anterior cruciate ligament (ACL) as the knee transitions from non-weight bearing (NWB) to weight bearing (WB). Therefore, any factors able to effectively reduce ATT during initial WB would theoretically reduce ACL loading. This study evaluated the extent to which hamstring musculo-articular stiffness (KHAM) is associated with ATT as the knee transitions from NWB to WB in 10 healthy females (19.9 ± 1.5 yrs, 1.65 ± 0.06 m, 62.3 ± 6.3 kg). Linear regression revealed that KHAM predicted 48.6% of the variance in ATT (R2 = .486, p = .025), with higher KHAM being associated with less ATT. KHAM is modifiable through training, and thus may be an important factor to consider from ACL injury prevention and rehabilitation perspectives
EFFECT OF FATIGUE ON ELECTOR SPINAE MUSCLES ON TRUNK POSTURAL KINEMATICS AND ELECTROMYOGRAPHYIC ACTIVITIS DURING REPETITIVE BACK SQUAT
Full text linkThe aim of the present study was to demonstrate the change of the trunk posture and electromyographic (EMG) activities of elector spinae muscle and lower extremity muscles during repetitive squat motion in two different conditions with or without the back muscle fatigue task. The results demonstrated that forward trunk inclination was significantly increased during the no-fatigue condition. In addition, the forward trunk inclination appeared to be greater in the pre-fatigue condition than the non-fatigue condition. In addition, the EMG activities in the erector spinae muscles were significantly increased in the non-fatigue condition, but not in the EMG activities in the pre-fatigue condition. Appropriate muscle strength must be necessary for squat exercise to maximize the training effects and to avoid lower back injuries
ELBOW AND WRIST JOINT LOADING DURING THE ROUND-OFF SKILLS IN MALE GYMNASTICS: A CASE STUDY
Full text linkElbow and wrist injuries are a major concern in elite male gymnastics. The aim of the current study was to investigate key elbow and wrist joint injury risk factors (internal and external kinetics) during different round-off techniques in male artistic gymnastics. One international level male gymnast performed 15 trials of a round-off from a hurdle step to back handspring with three different hand positions (parallel (5), T-shape (5) and reverse (5)). Synchronized kinematic and kinetic data were collected for each trial. Effect-size statistics determined differences between each hand position. In conclusion the T-shape technique demonstrated reduced vertical, anterior-posterior and resultant ground reaction forces. Differences in elbow and wrist joint kinetics indicated that the T-shape technique may prevent elbow and wrist joint from overload and reduces potential of injuries
HIP- AND BACK-PROTECTORS IN SPORTS AND EVERYDAY LIFE - EFFECTIVE PROTECTION?
Full text linkHip and back protectors are recommended to reduce impact forces when falling in sports or everyday life. This study analyzed the shock-reducing effect of 29 different hip and back protectors using a drop test and a Kistler force plate. Our results showed large differences between the single protectors. Measured peak forces often and quickly exceeded the supposed limit of bone fracture strength. Therefore sufficient safety does not seem to exist yet and protectors must not be overestimated in their protection potential. In our opinion protectors should have a certain thickness preferably a combination of hardshell and viscoelastic material. Hip protectors for sports still show large deficits. Back protectors only protect against direct contusion but not against axial compressions or cervical spine
BIOMECHANICS OF JUDO BREAKFALL FOR OSOTO-GARI IN ADOLSECENT JUDOKAS
Full text linkRegardless of relatively higher head injury occurrence, few studies have investigated the biomechanics of a judo breakfall technique in adolescent judokas. The aim of the present study was to demonstrate biomechanical characteristics of the breakfall technique performed by experienced adolescent judokas during the “osoto-gari” throw by comparing it with those performed by experienced adult and novice adult judokas. Motion data from the breakfall technique were collected with a three-dimensional motion analysis method. No significant differences were observed in the hip and neck movement patterns between the novice and the adolescent judokas (p > 0.05), but not between the experienced adult and adolescent judokas. This suggests that regardless of experience, the breakfall skill level of the adolescent judokas is not similar to that of adult experienced judokas
EFFECTS OF DIFFERENT HEIGHTS OF BOX DROP VERTICAL JUMP ON THE CHRONIC ANKLE INSTABILITY INDIVIDUALS
Full text linkThe purpose of this study was to investigate the effects of different height of box drop vertical jump DVJ) among the healthy control, coper, and CAI groups. Participants were asked to perform a box drop vertical jump and followed with a single-leg landing on the force plate. The DVJ height was 10cm, 30cm, and 50cm. Results from the current study indicated two major findings: Three groups showed difference in frontal plan and sagittal plane when doing 50cm DVJ task, In sequence for CAI ,coper and healthy group. Our findings indicated that different landing strategy of ankle joints exist among 3 groups
CURVE SPRINTING KINEMATICS EXHIBITED BY ATHLETES USING A SINGLE, TRANS-TIBIAL PROSTHESIS
Full text linkThe purpose of our study was to determine whether kinematics exhibited during the curve section of a 200 m sprint are influenced by ‘limb type’ (prosthetic vs nonprosthetic limb) or ‘prosthetic limb side’ (‘inside’ compared to the ‘outside’ of the curve). Two video cameras (60 Hz) were used to capture 13 male athletes using a single, trans-tibial prosthesis during an international, 200 m T-44 competition. From mixed-model ANOVA (p < .05), prosthetic and nonprosthetic limb kinematics were different, but differences were dependent on the prosthetic limb side. The inside versus outside prosthetic limb may be affected more due to the rotational influences that affect the inside and outside foot differently. Therefore, athletes whose prosthetic limb was on the inside may be at a disadvantage compared to those with an outside prosthetic limb