Gait analysis
Walking is the movement on which human locomotion is based and is essential for a person’s independence. Walking is the first form of physical exercise recommended by health authorities since it helps to prevent joint, heart and lung problems, while accelerating the metabolism and reducing the risk of diabetes[1]: it is therefore no wonder that restoring its full efficiency is the ultimate goal of multiple therapeutic protocols.
Ambulation is not as simple as it may seem: cognitive attention and muscle strength must be adequate and accompanied by adequate motor control, which is essential to coordinate sensory inputs and muscle contraction[2]. Therefore, a movement disturbance can affect several aspects, but always manifests itself with increased gait variability and asymmetry, leading to compensation, inefficiency and increased energy expenditure[3].
The presence of imbalances and dyskinesia has long been a subject of study and, over the years, increasingly sophisticated measuring instruments have been introduced, which have made it possible to overcome purely visual observation in favour of current Gait Analysis (GA)[4]. GA is acknowledged as a useful assessment method in the field of human movement research, since it makes it possible to objectify motor behaviour. In the clinical field, video systems, force platforms and electromyography probes are now commonly used to obtain information on kinetics, kinematics and muscle activation. A full examination also requires the involvement of several professionals (physiatrist, physiotherapist, biomedical engineer, etc.), which means that the total cost can be quite substantial[5].
However, the presence of bulky instruments and multiple operators observing the exercise can affect the quality of a patient’s gait. The ability to capture human movement in an ecological (natural) environment would thus bring various benefits, including the opportunity to assess different motor gestures with fast and minimal training, without major involvement of the subject analysed and therefore allowing more representative values to be obtained[6]. In order to encourage widespread use of GA, it is becoming increasingly important to abandon the use of large, expensive labs in favour of more flexible, portable technologies made available through technological advancement.
In this respect, one of the main answers comes from inertial and optical detection systems, such as Gyko and Optogait, which make it possible to analyse spatio-temporal and postural values: by quantifying these macro-parameters during the recovery process, potential problems can be identified in advance, which allows the next steps to be defined by objectifying trends, improvements or changes in specific motor patterns.
The most important, widely monitored parameters are:
- Duration (as a percentage of the gait cycle) of the gait phases; since walking is a cyclic movement, the gait cycle (or stride) has traditionally been defined as the period of time, or the sequence of events or movements during locomotion, which begins when one foot touches the ground and ends when the same foot touches the ground again. Each gait cycle (100%) is divided into a support phase (stance phase, usually about 60%) and a flight phase (swing phase, 40%). Both phases can be further divided into different sub-phases (see Figure 1).
- Step lengths and gait cycle length;
- Time parameters; the key parameters include step time (from the heel of one foot to the heel of the contralateral foot), cycle time and cadence. The phase in which the foot is in contact with the ground can be further divided into three subphases with different functions (see Figure 2).
- Gait speed.
- Dynamic trunk posture, which is monitored to detect any compensatory movements of the upper body (see Figure 3).
Once these values are available, it is important to assess the presence of asymmetries between the right and left limb, since high asymmetry can indicate difficulties in controlling balance and gait inefficiencies.
Finally, gesture variability must be limited, since an increase in its value could indicate a greater risk of falling, fragility, or deviations in muscle function and postural control[7].
Figure 1 The image shows the subdivision of the gait cycle into phases
Figure 2 The image shows the subdivision of the stance phase into sub-phases
Figure 3 The figure shows the postural parameters most commonly assessed in gait analysis: medial-lateral and anteroposterior movements and area of movement.
BIBLIOGRAPHY
[1] S. Hanson and A. Jones, “Is there evidence that walking groups have health benefits? A systematic review and meta-analysis,” Br. J. Sports Med., vol. 49, no. 11, pp. 710–715, Jun. 2015, doi: 10.1136/bjsports-2014-094157.
[2] “Human gait and Clinical Movement Analysis - Abu‐Faraj - - Major Reference Works - Wiley Online Library.” https://onlinelibrary.wiley.com/doi/abs/10.1002/047134608X.W6606.pub2 (accessed Sep. 03, 2019).
[3] “Gait disorders in adults and the elderly.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5318488/ (accessed Sep. 03, 2019).
[4] “The history of gait analysis before the advent of modern computers. - PubMed - NCBI.” https://www.ncbi.nlm.nih.gov/pubmed/17306979 (accessed Sep. 09, 2019).
[5] S. R. Simon, “Quantification of human motion: gait analysis—benefits and limitations to its application to clinical problems,” J. Biomech., vol. 37, no. 12, pp. 1869–1880, Dec. 2004, doi: 10.1016/j.jbiomech.2004.02.047.
[6] “Capturing Human Motion in Natural Environments - ScienceDirect.” https://www.sciencedirect.com/science/article/pii/S2351978915008872 (accessed Sep. 09, 2019).
[7] J. M. Hausdorff, “Gait variability: methods, modeling and meaning,” J. Neuroengineering Rehabil., vol. 2, p. 19, Jul. 2005, doi: 10.1186/1743-0003-2-19.
