Quantitative Kinetic and Kinematic Analysis
Markers are placed on anatomical landmarks of the human body to track movements which the body undergoes, this procedure Is fundamental In the development of quantitative Information of human movement. Utilizing Involves giving these landmark points, coordinates to then follow the points as the body moves In space and time. The body, Its segments and Joints can be determined using this data, linear and angular kinematics through its movement.
Joint reaction forces and muscles torques during movement can be determined when using linear and angular kinematics combined with kinetic information. Clinicians within the sports and exercise industry can use this information in conjunction with normative data and diagnostic assessment to assess the efficiency of movements along with assist in technique development.
This kinematics information can also be used in aid of the prevention of injury among athletes.
Theory Full kinematics description and accurate anthropometric measures Link-segment modeling In determining reaction forces and muscle torques Involves Inverse solution Step 1: (horizontal) Step 2: (vertical) Step 3: (rotation about centre of mass) Kinematics variables are found using the digitizing video footage Kinetic variables are measured using a type of force transducer Using a force plate scientists can measure the forces applied by the foot to the ground, known as ground reaction forces The ignited and directions of these forces apply to Newton’s Third Law, equal and opposite reactions A force-time curve can Indicate technique flaws Aim with calculating the reaction forces and muscle torques across the individuals ankle, knee and hip during the heel contact, mid-stand and toe-off of the gait cycle. Equipment 1 x Basher”* High Speed Video Cameras 1 x tripod Computer with Vision software and manual Force Platform Laptop with Occupiers Software Retro-reflective markers Tape measure Measurement calipers Procedure First session Data Collection and Processing
When preparing the force platform for data collection, a five second time interval was entered into the test duration box. By selecting the ‘zero button’ the force platform was calibrated. The weight (N) of the participant was taken by standing on the calibrated force platform and selecting Weight subject’, recorded in table 1 . Using the subjects’ right leg the following measurements were entered into table 1 .
Foot length Foot breadth Anomalous diameter Anomalous height Calf length Calf circumference Knee diameter Thigh length Mid-thigh circumference ASS’S breadth Using the tape measure the following anatomical landmarks were established and retro-reflective markers were attached.
Heel of Metatarsal II Heel Lateral Anomalous Knee Joint centre ASS’S Middle of the shank in line with the lateral Anomalous and knee Joint markers Middle of the thigh in line with the knee Joint marker and the greater trochee The subjects’ parameters were selected within the Vision MOTOS software and the values in table 1 were entered. Heel contact, mid-stance and toe-off were selected and the AD video was displayed on the screen. The camera was adjusted using the screen ND camera lens to ensure a clear, straight and bright image including all retro- reflective markers when the participant stood in the middle of the force platform. The camera was zoomed in as much as possible and focused on the entire plate and subjects’ body. While someone stood in the middle of the plate form horizontally video.
Once the recording was compete the left and right ends of the ruler seen on the computer were selected, the force platform was then recalibrated. The ‘start test’ button on the plate and the ‘record’ button in Vision MOTOS were selected Just prior to he participant walking over the plate with only their right leg coming in contact with the plate. The magnitude of the ground reaction force at heel contact, mid-stance and toe-off were recorded in table 2. Using the video controls under ‘digitize point’ in the Vision MOTOS software the frames of the foot during the heel contact was identified and the frame number recorded. The markers were digitized in the order indicated by the menu before repeating the steps for the mid-stance and toe-off frames.
Once these three frames were recorded the digitizing view was closed and he ‘process wizard’ was selected with the following chosen: Raw coordinates No gaps and no endpoint gaps Yes to filter the scaled coordinates No to quintet spine processing 100 Hazy for the output rate ‘AD Scales Coordinates Filtered’ was selected, the spread sheet cells which coincided with the frame heel contact were sited with the x and y coordinates of the markers recorded in table 2. This was repeated for mid-stance and toe-off frames. Second session: Calculations and analyzing results Results & Discussion From the calculations in the appendix it was found during the toe-off phase of gait he torque around the centre of mass of the ankle Joint was -12. NON.
This value describes the foot to be moving through plantar flexing during toe-off.
The torque around the centre of mass of the knee was 29. NON. This indicates the extensors of the knee are acting eccentrically to control the amount flexing that is occurring. As the participant is stepping down off the force plate this is not a normal action of gait, indicating the calculated value is not of what would happen in normal gait. Conclusion The aim of this experiment was met although there were some limitations found when conducting the procedure. Firstly the force platform was not flush with the ground surface, therefore creating a different movement or gait when walking up onto the plate.
