Academic journal article International Journal of Yoga

Understanding Vrikshasana Using Body Mounted Sensors: A Statistical Approach

Academic journal article International Journal of Yoga

Understanding Vrikshasana Using Body Mounted Sensors: A Statistical Approach

Article excerpt

Byline: Suhas. Yelluru, Ranjith. Shanbhag, S. Omkar

Aim: A scheme for understanding how the human body organizes postural movements while performing Vrikshasana is developed in the format of this paper. Settings and Design: The structural characteristics of the body and the geometry of the muscular actions are incorporated into a graphical representation of the human movement mechanics in the frontal plane. A series of neural organizational hypotheses enables us to understand the mechanics behind the hip and ankle strategy: (1) Body sway in the mediolateral direction; and (2) influence of hip and ankle to correct instabilities caused in body while performing Vrikshasana. Materials and Methods: A methodological study on 10 participants was performed by mounting four inertial measurement units on the surface of the trapezius, thoracolumbar fascia, vastus lateralis, and gastrocnemius muscles. The kinematic accelerations of three mutually exclusive trials were recorded for a period of 30 s. Results: The results of every trial were processed using two different approaches namely statistical signal processing (variance and cross-correlation). Conclusions obtained from both these studies were in favor of the initial hypothesis. Conclusions: This study enabled us to understand the role of hip abductors and adductors, and ankle extensions and flexions in correcting the posture while performing Vrikshasana.

Introduction

Yoga has been extensively studied as it has numerous benefits on the human health.[sup][1],[2] Yoga is a paramount tool to improve the mental and physical health of a person and also helps in stretching the muscles of the body. Yoga constitutes of innumerable poses called asanas that invigorate every part of the body, one among which is Vrikshasana, also known as the Tree Pose that stretches the legs, arms, and the back of the performer to help improve balance.[sup][3] The balance in the body is realized by the central nervous system (CNS). This provides a feedback strategy to control the center of gravity (CoG) from tipping off. This feedback strategy constantly is provided to the hip, knee, and ankle whose moments counter act the swaying of CoG.[sup][4] Studies of the postural responses to sudden small and slow external disturbances by support translation in the antero-posterior (A/P) direction found that most people reposition the CoG by swaying as a flexible inverted pendulum primitively about the ankles with little hip or knee motions, this type muscle activation is called as the "ankle strategy." Similarly, when postural responses to sudden and significant external disturbances by support translation in the mediolateral (M/L) and/or A/P direction found that most people reposition the CoG by swaying about the hip with little or no ankle motions, this type of muscle activation is called the "hip strategy."[sup][5]

Even attempting to stand still the body will be subjected to small variations such as vibrations in the M/L and or A/P plane. These minor perturbations do not prove to threaten the equilibrium.[sup][6] The projection of the center of mass can be easily maintained within the area of support bounded by the outer edges of the feet. It has been observed that people with CNS damage find it difficult to stand upright due to excessive sway in the M/L and/or A/P direction(s). According the standard Tree Pose described in,[sup][3] the participant lift one foot off the ground, eventually working their foot up to their calves, and then above their knees. The pressure of the foot exerted on the inner thigh causes the body reaction force to swing in the M/L direction.

The vast majority of investigations of quiet stance regarding the neuromuscular responses and strategies have been restricted to the sagittal plane.[sup][4],[7] However, the underlying motor mechanisms that suggest the hip abductors/adductors in addition to the ankle invertors/evertors control the lateral movement as concluded by Winter DA etal . …

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