Muscle use and joint force varied in five standing yoga postures
Research Study At A Glance
The Research Question Asked
Do muscle activation and joint force traveling through hip, knee, and ankle joints differ between five common standing yoga poses?
Type of Study
Within-subject experimental design
Study Participants (Sample)
Sample size: 11 total participants
- Average age 40.7 years old
- All participants were female
- Participants had a mean of 8.9 years of yoga practice experience
- Participants had an average of 7 years of yoga teaching experience
Methods
Researchers used kinematic data using motion analysis to calculate joint moments of force in five standing yoga postures. (Joint moments of force are a measure of the force going through a joint in a particular plane during movement.) The poses were chair, warrior one, warrior two, warrior three, and tree pose. Additionally, the research team used electromyography (EMG) to measure muscle activity of three quadriceps muscles and two hamstring muscles in the five standing poses.
Results
The joint moment of force differed between common standing yoga poses in the sagittal and frontal planes at the hip and knee joints. At the ankle joint, the joint moment of force only differed between poses in the sagittal plane. Quadricep muscle activation was highest in chair and warrior one and two poses. Hamstring muscle activation was highest in warrior three.
Conclusion
The force traveling through major joints in the lower body kinetic chain differed between common standing yoga poses, as did muscle activation. This indicates that the physical demands of standing yoga postures vary. The different physical demands of the poses make them more or less appropriate for different people.
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Background
Yoga is well-established as having many physical health and wellness benefits. It can improve strength and flexibility as well as positively impact physiological systems like the immune system and brain function. In particular, yoga is known as one way to build muscle strength. Because yoga uses many different positions to hold and move body weight, it is an effective way to build muscle strength.
There are different reasons why people might be interested in building muscle strength. Some people could seek out strengthening exercises solely to increase their overall fitness. However, others might be interested in cultivating strength to support rehabilitation after an injury. Therefore, it’s helpful to know more specifically how much we are using individual muscles and how much force is traveling through different joints when we do something like a standing yoga posture for strength-building. The study we summarize here explores those questions for five standing yoga poses.
Research question
Do muscle activation and joint force traveling through hip, knee, and ankle joints differ between five common standing yoga poses?
Study Participants (Sample)
Sample size: 11 total participants
- Average age 40.7 years old
- All participants were female
- Participants had a mean of 8.9 years of yoga practice experience
- Participants had an average of 7 years of yoga teaching experience
Research methods
In this study, researchers asked study participants to hold five standing yoga postures. The poses included utkatasana (chair), vrksasana (tree), virabhadrasana one (warrior one), virabhadrasana two (warrior two), and virabhadrasana three (warrior three). Participants held each yoga posture for ten seconds and repeated it three times. The research team randomly assigned the order of poses for each participant.
Researchers then collected kinematic data using motion analysis and calculated joint moments of force (JMOF). (Joint moments of force are a measure of the force going through a joint in a particular plane during movement.) The researchers then evaluated JMOF in the five standing yoga postures. The JMOF was calculated for the knee, hip, and ankle joints in both the sagittal and frontal planes. For warrior one and warrior two poses, the researchers calculated JMOF for joints of both the front and back legs. For chair, tree, and warrior three, they calculated JMOF for the right (or weight-bearing) leg only.
Additionally, the research team used electromyography (EMG) readings to measure muscle activity in the five standing poses. They evaluated the EMG of three quadriceps muscles, the vastus lateralis, vastus medialis, and rectus femoris. They evaluated muscle activity of two hamstring muscles, the biceps femoris and semitendinosus.
Results
There were significant differences in JMOF at the hip and knee joints in both the sagittal and frontal planes. There were differences in JMOF at the ankle joint in the sagittal plane, but not the frontal plane.
Joint moments of force
- JMOF at the hip joint in the sagittal plane was greatest in the front leg of warrior one
- JMOF at the hip joint in the frontal plane was greatest in the back leg of warrior two
- At the knee joint, JMOF in the sagittal plane was greatest in the back leg of warrior one
- At the knee joint, JMOF in the frontal plane was greatest in the back leg of warrior two
- JMOF of the ankle joint in the sagittal plane was greater in warrior two in the front leg than in warrior one in the back leg or warrior two in the back leg
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Muscle activation
- Muscle activation of rectus femoris was highest in chair pose
- The muscle activation of vastus lateralis was greatest in the front leg of warrior two
- Muscle activation of vastus medialis was greatest in the back leg of warrior one
- The muscle activation of both biceps femoris and semitendinosus were highest in warrior three
Why is this relevant to yoga practitioners?
The results of the study we summarized here point out the difference in physical demands of several standing yoga postures. This information is highly useful for informing the design of rehabilitation protocols using yoga, which was the goal of the study. This kind of information can help physical therapists, personal trainers, and yoga practitioners decide which poses to include in their routines when they want yoga to be a part of their rehabilitation plan. For example, based on muscle activation, chair pose, warrior one, and warrior two could all be effective at strengthening the quadriceps. However, the high JMOF in warrior one and two going through the knee in the frontal plane as well as the hip in the sagittal and frontal planes mean these poses might not be the best choice for someone experiencing osteoarthritis in the knees or hips.
Conclusion
This study points out something we are probably aware of as yoga practitioners, that yoga postures demand different levels of effort. Keeping that in mind each day as we do our practice can help us tailor our practice to meet our energy level and situation. An understanding of what kind of physical demands individual poses have can help teachers, physical therapists, personal trainers, and others choose the best poses for an individual’s personal circumstances.