**2. Background**

#### **2.1 The philosophy of yoga**

Yoga, an ancient mind-body movement practice, originated in India more than five millenniums ago. Also commonly referred to as a meditative movement practice, it involves movement, a meditative state of mind, breath focus and deep relaxation for purposes of enhancing or healing the physical, mental and emotional well-being [18].

Yoga appears to be a form of alternative medicine [19], and its philosophy is based on the eight limbs schematised by Maharishi Patanjali, one of the main pillars of classical yoga. These eight limbs comprise yama (universal moral ethics), niyama (internal attitudes for personal discipline), asana (yoga posture), pranayama (expansion of life force), prathyahara (withdrawal of senses), dharana (contemplation of one's true nature), dhyana (meditation) and samadhi (liberation) [20].

The first three limbs or stages – yama, niyama and asana, are considered the outward quests (bahiranga sadhana). With the practice of yama and niyama, the practitioner works towards keeping his passions and emotions under control, while the asana component, if practised diligently, keeps the body strong and healthy, and in harmony with nature. Breath regulation and mind control take place in the next two stages, that is, pranayama and prathyahara. Since these stages work at the inner level, they are known as inner quests or antaranga sadhana in Sanskrit. The last three stages – dharana, dhyana and samadhi, elevate the practitioner into the deeper recesses of the soul [21].

As yoga is not a religion or a cult, anyone regardless of age, creed or gender can learn and practise it. For the genuine seeker, whose desire is to experience the universal self within, the practice of yoga is an unbroken journey. Nevertheless, this ancient practice can be simplified and performed in a number of ways to suit the practitioner [22].

The practice of yoga is so flexible that the practitioner can simply utilize some, if not all, of the limbs to their own comfort. In a conventional 1 h yoga session, it is not uncommon to have the asanas integrated with practices of pranayama, prathyahara, dharana and dhyana. Having said that, there are many styles of yoga; precision and alignment, asthanga yoga, flow yoga, asana yoga, gentle yoga and hot yoga are some of the common styles [23].

#### **2.2 Benefits of yoga**

The practice of yoga brings about tremendous benefits to the body and mind. In the past nine decades, empirical research has been carried out on the techniques of yoga to test its credibility. Pioneer experiments conducted by Swami Kuvalayananda in 1924 focused on parameters like heart rate, blood pressure fluctuations, and intra-esophageal air pressure during the performance and also after the practice of asanas and pranayama [24].

Due to promising results, yoga has since been classified by the National Institute of Health as a form of complementary and alternative medicine, and people from all walks of life have incorporated this scientific practice into their lifestyles [25].

Unlike other forms of exercise, yoga focuses on being present in the moment. Hence, the practitioner needs to be mindful regardless of whether they have assumed a static position while holding an asana for a couple of breaths, or in motion especially during the performance of an asana. Preliminary research has advocated that yoga may increase levels of mindfulness in the practitioner [26, 27]. The asanas when performed steadily and joyfully, are useful in preventing and correcting structural imbalances in the body [28].

As this ancient science also appears to be a form of moving meditation, there have been suggestions that practitioners are more likely to be engaged in the movement aspect of yoga as it stimulates the cognitive processes related to mindfulness [29]. In addition, the meditative movement, which coordinates each movement with the breath systematically, increases physical endurance in the practitioner

over time. As the muscles recurrently contract with more force while performing a particular movement, their strength eventually increases. An example would be in the classical cobra pose (bhujangasana). In this pose, the practitioner starts of by lying flat facing downward on the mat. As the upper torso and head are lifted of the mat upon inhalation, the back extensors are engaged and contracted strongly. Hence, if the position is held long enough (while breathing normally), and if the movement is repeated a couple of times in each practice, the back muscles will be strengthened [30].

Muscles and connective tissues are stretched in asanas to increase flexibility. Regardless of whether the stretch is with or against gravity, the body will experience a stretch, thus increasing flexibility [30]. Unfortunately, in the current situation today where many, who work from home, pay little attention to their sitting position, the structural alignment is greatly compromised. Certain sporting activities like tennis and football, which require strenuous use of one side of the body, are equally to be blamed too. Asanas taught in yoga have been known to prevent and correct structural misalignments in the body.

Having said that, existing research unveils that the benefits of yoga are not limited to only correcting structural misalignments, enhancing stretching and improving flexibility; yoga also enhances emotional and psychosocial health and brings about an increase in proprioceptive and interoceptive awareness [31, 32]. There have been propositions that if yoga is practised consistently, it has the ability to induce neuroplasticity i.e., changes in the neural pathways of the brain, thus improving psychological skills [33]. This augurs well for the yoga practitioner as it suggests that the brain can be rewired just like a muscle in the physical body.
