ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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ROTATOR CUFF ACTIVATION DURING THE OLYMPIC SNATCH UNDER VARIOUS LOADING CONDITIONS
Get PDFThe current study examined rotator cuff (RTC) muscle activation levels during different phases of the snatch under varied loading conditions, and evaluated shoulder abduction (ABD) angle during the catch. Nine male Olympic weightlifters currently training for competition had surface EMG electrodes attached to their supraspinatus, infraspinatus, and teres minor, then performed two lifts at 40, 60, and 80% of their maximum snatch. 2-D video was used to record each lift and synchronized with the EMG readings to evaluate RTC muscle activation. Markers were placed on the participants’ upper extremity to evaluate shoulder ABD angle during these trials. Shoulder ABD angle at the catch did not differ between loading conditions. RTC activation varied throughout the snatch with the supraspinatus and infraspinatus becoming most active during the turnover and catch phases of the lift while the teres minor is most active during the first pull and transition
EFFECT OF A STRETCHING PROGRAM ON OVERHEAD ATHLETES WITH A STIFF AND PAINFUL SHOULDER
Get PDFOverhead athletes are more at risk of suffering shoulder injuries or/and developing shoulder pain. Stretching programs have been shown to successfully reduce pain for this population. However no study has provided a global overview of the effects of stretching. The present study evaluated the evolution of the pain, the strength of the shoulder muscles, potential instabilities or lesion of the shoulder as well as the 3D scapular kinematics of 10 overhead athletes having a painful and stiff dominant shoulder. Our results show a significant decrease of the pain and of the positive impingement syndrome tests. The kinematics of the scapula reveals a more upward rotation of the scapula after the stretching, which may reduce the risk of sub-acromial conflicts. The strength of the internal and external rotators of the shoulder is not modified by the program
DEVELOPMENT OF MULTISTEP DROP JUMP TEST BY USING DIFFERENT DROP HEIGHTS
Get PDFWe used different drop heights to evaluate the drop jump (DJ) test in elite athletes. Male jumpers (n=10) performed the test at 0.3, 0.6, 0.9, and 1.2 m. Jumping motions in the sagittal plane and the ground reaction force were recorded using a high-speed camera and force platform, respectively. The amount of negative work by 3 lower extremity joints increased with increased drop height of the DJ test, mainly at the hip joint. There were different performance patterns on the DJ test and lower extremity power output with an increased drop height according to individual characteristics of elite jumpers, compared with the average pattern. Jump performance was correlated with the DJ index at DJ1.2 and the decreased rate of the index from DJ0.3 to DJ1.2. Thus, to evaluate elite jumpers’ performance, various height ranges including a higher drop height should be used
EFFECTS OF A MANUAL THERAPY ON TIBIOFEMORAL JOINT FORCES IN PATIENTS WITH ACUTE ANTERIOR CRUCIATE LIGAMENT RUPTURE
Get PDFThe purpose of this study was to analyse the acute effects of the manual therapy RegentK on tibiofemoral joint forces and lower limb muscle forces in patients with an acute unilateral ACL rupture. Eight patients with an acute ACL rupture were recruited. Tibiofemoral joint forces and quadriceps, hamstring and gastrocnemius muscle forces were analysed during walking pre and immediately post the one time intervention using a musculoskeletal model.Results showed that tibiofemoral joint loading and muscle forces were altered in the injured compared to the uninjured limb, but no significant effect of the intervention could be shown. Joint and muscle force patterns, however, were highly individual. For future analyses the comparison with a matched-control group and the use of different methods to detect waveform-changes are recommended
OAR BLADE POWER OUTPUT AND BOAT VELOCITY IN CONTEXT OF ROWER LEG, KNEE AND TRUNK COORDINATION IN SCULLING
Get PDFThe purpose of this study was to test the feasibility of a method estimating oar power output and boat velocity in relation to rower coordination in terms of kinematics of knee, trunk and elbow, derived from a set of 17 wireless Inertial Magnetic Measurement Units (IMMUs) positioned on rower body segments, oars and boat, recorded in actual on water varsity rowing at competition speed. Although in these experiments no 2nd method was present for absolute validation, the practical feasibility, the repeatability within bouts, between similar bouts as well as the consistencies in similarities and differences between different bouts and different rowers support the feasibility of a future coach supporting tool based on this technology
TRIAL STABILISATION OF RUNNING BIOMECHANICS WITH SHOE FAMILIARISATION IN TRAINED DISTANCE RUNNERS
Get PDFAppropriate trial sizes for biomechanical studies examining running shoe functionality are important to ensure valid insights into injury prevention strategies. The study aimed to examine the influence of shoe familiarisation on trial stabilisation in trained distance runners. A sequential averaging analysis was used to define trial stabilisation of biomechanical measures obtained from two testing conditions (new shoe and familiarised shoe). Between condition group analyses suggested similar trial stabilisation irrespective of shoe familiarisation (group mean ±SD: new: 7.5 ±2.0 trials; familiarised: 7.0 ±2.0 trials). Within group analyses identified variations in trial stabilisation according to the participant, condition and measure. An eight trial protocol was advocated for participantcondition analyses in longitudinal studies examining shoe functionality
COMPARISON BETWEEN VELOCITY PROFILES OF THE ASSISTED TOWING METHOD AND FREE SWIM VELOCITY
Get PDFActive drag is computed based upon three variables: free swimming velocity, towing velocity and belt force. Mason et al. (2011) assumed that the shape of towing velocity profile was similar to the shape of free swim velocity profile. The aim of this study was to compare these two velocities profiles. Four national male swimmers performed two free swim trials using a velocity transducer and two assisted towing trials using the dynamometer. Relative maximum to minimum velocity of the mean value for free swimming trials and the towing trials was approximately 19% and 13% respectively. The different phases of the right arm stroke for both velocity profiles were compared and the result showed significant differences between all phases except the downsweep phase. It can be concluded that using the assisted towing method may change stroke mechanics
COMPARISON OF KINETICS OF THE LEG JOINTS IN SEOI-NAGE BETWEEN ELITE AND COLLEGE JUDO ATHLETES
Get PDFThe purpose of the present study was to identify biomechanical factors that could be used for the evaluation of seoi-nage technique by comparing the techniques of elite and college-level judo athletes. The motion data of the seoi-nage were collected on three male elite judo athletes and nine male student judo athletes using a three-dimensional motion analysis technique and qualitatively compared. This study found that the peaks of the knee flexion torque, knee negative power, hip extension torque and hip positive/negative power on the swing leg of elite athletes was much greater than those of the college athletes. These indicated that the knee and hip joint contributed to the mechanical energy absorption of the tori’s body in the early phase and generated the positive power in the throwing phase
VALIDATION OF AN IMU-SYSTEM (GAIT-UP) TO IDENTIFY GAIT PARAMETERS IN NORMAL AND INDUCED LIMPING WALKING CONDITIONS
Get PDFThe purpose of this study was to investigate an IMU system (GaitUp) with respect to validity in normal and induced impaired walking by comparing with a state-of-the-art 3D motion capture system. The gait of nine participants was analysed collecting data simultaneously with the GaitUp (Physiolog) placed at each foot and an eight camera motion capture system (Vicon) at 200 Hz each. Participants walked in normal and induced limping (elevation of one shoe) conditions at three walking speeds. For all conditions the two systems yielded similar results regarding the standard gait parameters (gait cycle time, stride length, stride frequency and gait velocity) according to absolute differences and correlation coefficients. GaitUp gathers fairly valid and reliable data in normal and limping walking in a range of walking speed between 0.9 and 2.0 m/s
DESIGN, VALIDATION AND APPLICATION OF AN UNOBTRUSIVE OAR FORCEANGLE MEASUREMENT SYSTEM
Get PDFFeedback is necessary for the improvement of motor performance. Elite level athletes in particular require accurate and detailed kinematic and kinetic information for improvement. The purpose of this study was to design, build, validate and apply an unobtrusive oar force-angle measurement system for the evaluation of on-water rowing performance. Performance measurement systems must also meet the criteria of accuracy, unobtrusiveness, reliability, quality visualisation and affordability. Using high quality IMU and force measurement technology a system (RowIMU) was designed and built that met these criteria. Results for horizontal, vertical and feather angle of the oar and the normal handle force were obtained and reported. The system provided innovative and useful information for coaches and rowers