Importance Of Quantifying Athletes' Whole-Body Kinematics

In the world of sports, athletes, coaches, physios and sports scientists are constantly seeking ways to gain a competitive edge. While talent, training, and strategy play crucial roles, understanding the intricate details of an athlete's movement can make an important difference. This is where the quantification of kinematics comes into play. We can delve deeper into the mechanics of human movement, providing valuable insights to optimise performance, mitigate the injury risks, and maximise athletic potential.

Here are some specific examples of this:

1. Enhancing Performance: Quantifying an athlete's kinematics allows for a detailed analysis of their movement patterns, range of motion and technique. By capturing and analysing joint angles, velocity, acceleration and force production, coaches and trainers can identify areas for improvement. Whether it's refining a golf swing, perfecting a tennis serve, or optimising running mechanics, kinematic analysis provides invaluable feedback to enhance an athlete's performance.
2. Injury Risk Reduction: Athletes are prone to injuries due to the physical demands and repetitive nature of their sports. Quantifying kinematics enables the identification of movement asymmetries, imbalances, or faulty mechanics that may contribute to the risk of injury. By detecting these biomechanical issues early on, coaches and sports scientists can implement targeted interventions and corrective exercises to mitigate the risk of injury and enhance an athlete's overall movement competency.
3. Personalised Training Programs: Every athlete is unique, and a one-size-fits-all approach to training may not yield optimal results. By quantifying an athlete's kinematics, coaches can develop personalised training programs that address specific movement patterns and biomechanical characteristics. By tailoring training regimens to an athlete's individual needs, coaches can optimise performance gains and help athletes reach their full potential.
4. Objective Performance Assessment: Subjective assessments of performance can be influenced by bias. Quantifying kinematics provides an objective and data-driven approach to evaluating an athlete's progress. By measuring and analysing key performance metrics, coaches can track improvements over time, set realistic goals, and make informed decisions based on reliable data. This objectivity also helps athletes gain a better understanding of their strengths, weaknesses, and progress, fostering motivation and a growth mindset.
5. Talent Identification and Talent Development: Quantifying kinematics is not only beneficial for established athletes but also plays a vital role in talent identification and holistic development. By assessing the movement mechanics of young athletes, coaches and talent scouts can identify individuals with exceptional physical attributes and potential. Early identification of talent allows for targeted training and development programs, nurturing young athletes to reach their full athletic potential.

Quantifying kinematics both quickly and accurately is hard and coaches and physios still mostly judge athlete movement by eye. However, there are various technologies in use and these are summarised here:

Marker-Based  Motion Capture Systems: Motion capture systems have long been a staple in kinematic analysis. These systems utilise a combination of cameras, markers and algorithms to track the movement of athletes in three-dimensional space. By placing reflective markers on specific body landmarks,  motion capture systems can capture the position and orientation of each marker as the athlete performs various movements.  This data is then processed to reconstruct the athlete's kinematics accurately. Motion capture systems offer high accuracy and detailed information about joint angles, range of motion, and movement patterns, but this is a time-consuming process. Accordingly, these methods are more popular choices in research settings and are less used in amateur or even professional sports settings.

Inertial Measurement Units (IMUs): IMUs are wearable sensors that contain accelerometers, gyroscopes, and sometimes magnetometers to measure an athlete's motion. These sensors are typically attached to specific body segments or incorporated into specialised garments. IMUs can provide real-time data on an athlete's acceleration, orientation, and angular velocity. By collecting data from multiple sensors, IMUs can estimate joint angles and movement patterns without the need for external cameras or markers. IMUs offer portability, versatility, and the ability to monitor athletes' kinematics during actual game situations, making them popular for field-based assessments and in-game analysis.

Pressure Mapping Systems: Pressure mapping systems involve the use of sensor arrays embedded in surfaces such as floors, mats, or insoles. These sensors capture data on the distribution and magnitude of forces exerted by an athlete's body. By analysing the pressure patterns, coaches and sports scientists can gain insights into foot strike patterns, balance, and weight distribution during different movements. Pressure mapping systems are particularly useful for assessing gait, running biomechanics, and sports-specific movements that involve contact with the ground.

Wearable Technology: The rise of wearable technology has significantly impacted the quantification of athletes' kinematics. Smartwatches, fitness trackers, and specialised wearables can now capture and analyse some movement data in real-time. These devices often integrate accelerometers, gyroscopes, and heart rate monitors to provide insights into an athlete's speed, distance, step count, and even sleep patterns. While these wearables may not offer the same level of detail as other methods, they provide a convenient and accessible way to monitor general movement patterns and provide feedback to athletes and coaches.

These methods are usually expensive and require too much set-up time to be used to measure whole-body kinematics on a routine basis. They are used in biomechanical laboratories or in some cases single wearables are used to track performance or injury risk. However, setting up an athlete with full body markers or sensors is usually only done at the end of the rehab cycle by professional athletes, or in a research setting, where additional technical resources can be used to process and interpret the results.

As these methods aren’t scalable and accessible for all the areas mentioned above, physios and coaches still consider that there is a ‘huge gap’ and many professionals end up bridging the gap with video and slow-motion, or simply by observing. According to Des Ryan, as an applied example of a soccer academy, the Sport Science and Sports Medicine support team could have up to 160 athletes who are screened using the Functional Movement Screen (FMS), 3-4 times/year over 4 years, a team will record, store and interpret approximately 30,000 individual scores for the FMS alone. In addition, this is only one of the physios' tasks, in most clubs the ratio of physio and coaches to athletes is quite small, and therefore remembering their screenings are a fraction of their daily load, which is a difficult task heightened by a lack of resources and subjected to recall bias.

Advancements in computer vision and artificial intelligence (AI) have opened new possibilities for kinematic analysis. With the help of deep learning algorithms, computer vision systems can track and analyse an athlete's movement using video footage from a single device. By training AI models on vast amounts of annotated data, these systems can identify joint locations, infer joint angles, and detect specific movement patterns. This approach offers scalability, as it can be applied to large-scale data analysis, such as analysing performance across entire teams or even multiple sports. Nevertheless, it is essential that the accuracy and consistency of these technologies is validated for the specific applications in order to  remain biomechanically accurate.

Finally, if quantifying whole body kinematics was more accessible, it wouldn’t only be applicable for elite athletes. Enhancement of movement quality could be taught from schools and academies, where in many cases coaches are volunteering, and have no training, or their training is limited. Such a system could improve coaching competency and lead to more efficient/effective programme delivery. It becomes a duty of care, which would make future athletes, start their careers well educated in the importance of moving well, but would also help keep kids healthier and safer.

The quantification of kinematics can revolutionise the way we understand and optimise athletic performance. By harnessing the power of motion analysis technologies, we can unlock valuable insights into an athlete's movement patterns, technique and potential for improvement. From enhancing performance and reducing injury risks to personalising training programs and objectively assessing progress, kinematic analysis empowers coaches, trainers and athletes to take their performance to new heights. In the relentless pursuit of excellence but also to protect the athletes, quantifying the kinematics of athletes is an essential tool that can make a tangible difference in the world of sports. And if we make it more accessible and easier to use, we can ensure not only the elite see these benefits.