Several measurement approaches have been used to examine the performance of elite athletes today. It is most commonly done in a laboratory where physiology and biomechanics can be tested and analysed. Moreover, the performance of elite athletes is also measured during competition.
These measurements enable coaches to effectively work with athletes to enhance their performance. Advancements in microelectronics and microtechnologies have facilitated measurement of elite athletes in a natural training environment.
The applications of inertial devices in elite sports have been discussed in detail by James D.A of the Griffith University in a paper issued in 2006.
The utilization of gyroscopes and accelerometers for measuring human motion at various points of the body has been well established already. However, interpreting these data and converting it into metrics for use by athletes, coaches and scientists is a great challenge. On the other hand, interpretation of sensor data such as characterization and pattern recognition of activities, and energy expenditure have achieved greater success.
Similarly, researchers from the University of Calgary, Alberta, Canada have discussed the benefits of using orthotics and inserts in a paper issued in 1999. Scientists hope that movement-related injuries can be prevented by employing inserts or orthotics. However, the knowledge on functioning of inserts or orthotics is very limited.
Changes in the movement of skeletal muscles due to orthotics or inserts were found to be small and irregular. These inserts also provide impact cushioning of less than 10%. The foot incorporated with such inserts has various sensors for detecting input signals having subject- specific thresholds. It was found that the subjects with similar threshold levels respond to the movement pattern in a same way. The team proposed a concept of minimizing muscle movement with the use of inserts or orthotics based on these data.
The sole of a shoe acts as a first filter, the orthotics or inserts acts as a second filter and the plantar surface of the foot acts as a third filter for the force signal that in turn serves as an input variable on the shoe. The filtered information is then transferred to the central nervous system for providing a subject specific dynamic response. Therefore, the insert or orthotic increases performance of athletes, makes them feel comfortable and reduces muscle activity.
In 2005, the Stanford Taekwondo Program, Impact Measurement and the Palo Alto Research Center collaboratively introduced sensor technology for use in a martial arts sparring ring. The system, SensorHogu employs piezoelectric force sensors on body protectors for helping Taekwondo judges and referees in accurately scoring the sparring matches.
In 2005, S. Brady et al from the Dublin City University developed novel smart textiles using conducting polymer coatings laid on a foam substrate. It makes the foam conductive, soft and porous and retains the tactile properties of the original material. The material thus becomes sensitive to pressures exerted from all three dimensions, which makes it suitable for use in wearable sensors used in medical and sport applications.
Sport movement analyzer and a training device is used for detecting, monitoring, correcting and re-creating movements of a user in real-time during a sport. It features an analyzer attached to the wrist of a user involved in sport activities. During a sport movement, a sensing unit present in the analyzer provides signals that represent the movement of the wrist at different swing positions. The signals are then processed by a processor in the analyzer for measuring the sport performance parameters along the swing path.
Stored programs in the analyzer help the processor in processing the signals for display to the user. In addition, the device has the history of previous sport performances of the user stored inside it for comparison with current performances.
Commercial Sensors in Sport - Examples
Some of the examples of commercial sport sensors include the following:
- Elliott Fight Dynamics Gloves – The sensors are located at the lower inner side of the wrist strap region of the gloves for recording the performance of a player. The sensors are placed such that they are exposed to minimum impact during punches. These sensors are capable of tracking heart rate, force of punch and hand speed of the player. The information is instantly is sent to the personal computer or Smartphones from the gloves through the wireless connection, so that the performance and the progress of the user can be efficiently monitored.
- Arrowspeed Radarchron® - It is a small, inexpensive microwave Doppler radar velocity sensor developed by Sports Sensors, Inc. for assisting archers in measuring and optimizing the performance of the bow and arrow equipment. The device can be secured to a threaded port on the end of the stabilizers. It is also provided with an adaptor plate for allowing vertical positioning of the radar with respect to the arrow flight path. It can even measure the speed of carbon/graphite or metal arrows.
- Break Speed Radar™ - It is a microwave Doppler radar that assists players of Pocket Billiard games in developing a stable and powerful opening break shot by providing an instant reading of ball speed with precision accuracy to one-tenth of an mph. It is also useful for bowlers in measuring the ball release speed.
- Swing Speed Radar® - This technology is a small microwave Doppler radar velocity sensor that is used for measuring the swing speed of golfers, the football speed of football place-kickers, the bat swing speed of baseball and softball players and the racket swing speed of tennis players.
Swing Speed Radar® by Sports Sensors, Inc. Video by Ignition Golf.
Clinical testing of analysis and improvement of athlete’s performance has been traditionally performed in laboratories having the required instrumentation and controlled environment. Accelerometry and other sensing technologies play a vital role for measuring physical activity.
However, technology advancements have enabled engineers to transform clunky, conspicuous monitors into small, ergonomic, and convenient research devices. These new devices can be used to collect information on overall physical activity including physiological state of the subjects and location for several days/weeks during their regular lives.
Some devices will make use of mobile phones for detecting and responding to physical activity in real time, remote compliance monitoring and creating new opportunities in measurement.
Sources and Further Reading
- S. Brady et al, The Development and Characterisation of Conducting Polymeric-based Sensing Devices, Synthetic Metals, 2005, 154 (1-3) : 25-28
- Chi, E.H, Introducing wearable force sensors in martial arts, Pervasive Computing, IEEE, 2005, 4 (3) : 47-53
- James.D.A, The Application of Inertial Sensors in Elite Sports Monitoring, The Engineering of Sport 6, 2006, 289-294
- How the System Works - Elliott Flight Dynamics
- Nieminen et al, Sport Movement Analyzer and Training Device, US Patent Application Publication, 2007.
- Arrowspeed Radarchron® - Sports Sensors