Yoga is commonly viewed as a safe and effective means of increasing the strength, flexibility, and functional capacity of seniors. For example, the National Recreation & Park Association recommends Yoga as a “total-solution exercise” for older adults [1]. Similarly, the National Institute of Diabetes & Digestive & Kidney Diseases publication Healthy Eating and Physical Activity across Your Lifespan states, “yoga combines balance, flexibility, and strengthening benefits [2].” While we concur that Yoga holds great promise as a path to wellness in seniors, little scientific research quantifies to the physical demands, efficacy, and safety of Yoga programs for older men and women. Formal study is warranted because we must understand the potential benefits and risks of Yoga in seniors – and how to maximize the former and minimize the latter. As a step toward this end, we conducted the Yoga Empowers Seniors Study (YESS). This manuscript provides a brief overview of the rationale and design of the study but mainly details the asana series that were used in the project.

In general, older adults have less joint range of motion, less strength and poorer balance than do younger persons [3]. With aging come more limiting musculoskeletal conditions, such as osteoarthritis and low back syndromes that likely put seniors at higher risk of musculoskeletal side effects from yoga and that demand targeted asana modifications. In our prior clinical trial of yoga for excess thoracic curvature (hyperkyphosis), conducted in men and women aged 60- 90 years of age, approximately 60% of the 120 participants developed musculoskeletal soreness and/or pain significant enough to require additional variations of their poses (versions adapted for seniors with kyphosis were already being used) [4]. Further, participants with preexisting musculoskeletal conditions (even quiescent ones) developed side effects earlier in the hyperkyphosis study than did those without pre-existing conditions.

While yoga for seniors may have several positive outcomes beyond the physical, YESS is focused on achieving muscular strength gains in a safe manner. In particular, YESS is attempting to create asana series that train major muscle groups, especially those that are associated with fall risk, such as the hip abductors [5,6]. We used a biomechanics approach to capture information about the physical demands placed on the muscles and joints by the specific asanas we employed, as well as the functional performance adaptations (e.g. gait, strength or balance changes) associated with practicing these postures. In-depth descriptions of the biomechanics methods and results will be the topics of other reports. Here we will present the senior-adapted YESS asana series and the additional modifications provided when participants had physical limitations.

Study design and setting

The Yoga Empowers Seniors Study (YESS) was a single-arm, nonmasked, pre-post, intervention development study. Study activities took place at the YESS research offices at the University of California at Los Angeles (UCLA), the University of Southern California (USC) Musculoskeletal Biomechanics Research Laboratory (MBRL) and the TruYoga studio, Santa Monica, California. USC and UCLA Institutional Review Boards approved the protocol and participants gave written, informed consent.

Figure 1 summarizes the YESS design. To ensure a small Yoga class size, the intervention was delivered to two separate groups, with lagged start times. Each group had 2 weeks of preparatory Yoga classes (4 classes) prior to the first set of baseline biomechanics and physical performance measures, because they had to learn the yoga postures before they could undergo baseline biomechanical testing while performing the postures. Participants next attended twice-weekly, onehour Yoga classes for 16 weeks, during which the Series I asanas were taught. We made interval biomechanics and physical performance measures after the first 16 weeks. Series II was instructed twice-weekly for 16 additional weeks and final biomechanics and performance measurements were taken.

Recruitment and eligibility

Participants were recruited using mailing lists, physician referrals, flyers and newspaper advertisements. Initial eligibility (e.g., age) was evaluated by phone; at an in-person screening, additional inclusion and exclusion criteria were assessed. Women and men aged 65 years of age were eligible. The following were exclusions: active angina; uncontrolled hypertension (SBP > 160 or/and DBP > 90); high resting heart rate (greater than 90) or respiratory rate (greater than 24); unstable asthma or exacerbated chronic obstructive pulmonary disease; cervical spine instability or other significant neck injury; rheumatoid arthritis; unstable ankle, knee, hip, shoulder, elbow, or wrist joints; hemi paresis or par paresis; movement disorders; peripheral neuropathy; stroke with residual deficit; severe vision or hearing problems; walker or wheelchair use; not able to attend in-person classes; has not had checkup by regular provider within 12 months (if not taking any prescription medications) or in the past 6 months (if any regular medicines taken). Participants also had to execute the following safety tests stably and independently: transition from standing to recumbent on the floor and reverse; lift both arms to shoulder level; stand with feet side-by-side for 30 seconds; and stand with feet hip-width apart for 60 seconds.

Measurements

Baseline, interval and final visit measures included: 1) demographic descriptors, medical conditions, health behaviors (physical activity, smoking and alcohol use) and health-related quality of life, using standardized questionnaires; 2) anthropometrics; and 3) biomechanical measures and physical performance testing. Measurements will not be described further herein, but will be the subject of additional papers describing results.

Yoga intervention

We delivered a Yoga intervention, 2 days per week, one hour per session, for 32 weeks (exclusive of preparatory sessions (Figure 1). We used Hatha yoga, which teaches asanas (postures) and pranayama (breathing). By emphasizing mental and physical focus during the practice of asanas, Yoga attempts to build concentration and body awareness. We created two sets of postures, Series I and Series II, designed to be progressive (i.e., to advance in difficulty) and to train major muscle groups that are integral to conducting activities of daily living, including: the shoulder/upper extremity (necessary for reaching, for example, to procure items from an overhead cabinet and for carrying light loads such as groceries or parcels); trunk stabilizers (for balance); and hip/lower extremity (central to static and dynamic balance and to the capacity to transfer safely from sitting to standing). We used modified versions of standard asanas, tailored in a manner that we believed to be suitable to the ambulatory senior population for whom this intervention is intended.

Design of the YESS asana series

Series were constructed to meet the following training goals: 1) to offer a safe, yet challenging, practice for ambulatory seniors; 2) to include a range of foundational asanas, targeting functional muscle groups (defined above); 3) to incorporate asanas intended to improve balance; and 4) to include asanas aimed at increasing joint range of motion (JROM). Specific postures intended to achieve each of the 4 training goals were selected by GAG, LK and GS, based on their combined knowledge of yoga, physical therapy and movement science. Reproducibility was also a specific goal. We therefore modeled the YESS program after the Ashtanga School, which uses a standard set of opening and closing postures, and variable middle series, which progress in difficulty. Each set of Ashtanga middle postures is preset and is done in an un changing order. Analogously, YESS used set opening and closing sequences and two ordered, progressive middle sequences, termed Series I (first half of the study) and Series II (second half of the study). Using this standardized approach facilitates describing what we taught and makes the intervention transparent to both the research and the teaching communities. An additional benefit of the ordered, standardized series is that it constrained the poses to a number that we could feasibly study in the biomechanics laboratory.

Implementation of the YESS series

During the preparatory instruction (first 2 weeks) Series I poses were gradually introduced. At the end of the preparatory period, all opening, middle and closing poses had been taught. Participants were therefore ready to attend their first biomechanics session, where they were instrumented and measured while practicing each pose under the supervision of the yoga instructor (LK). Series I was then taught twice per week, for 16 weeks and was followed by a second set of biomechanics assessments. The same process was repeated for Series II (Figure 1).

After the second week of teaching the full Series I sequence, we determined that 4 opening postures, 12 middle postures and 4 closing postures was an overly ambitious agenda for a one-hour Yoga class – there was no time to hone in on matters that needed clarification,amplification or illustration. We therefore inaugurated a rule that was maintained throughout the remainder of Series I and all of Series II: in each class, 3 middle sequence postures could be omitted. But, the skipped postures alternated, so that no posture was left out for more than 3 weeks running. We recorded the postures performed in each class, to assure that this mandate was met. Teaching 9 rather than 12 middle sequence postures during each class allowed the instructor time to provide in-depth, highlighted teaching of the intended muscular actions, alignment, etc.

Figure 1: Yoga Empowers Seniors Study (YESS) Design..

Illustration of Posture		English Name Sanskrit Name	Description of pose
Opening Postures
		3 Part Breathing, Recumbent Dirga Pranayama	Isolation of inhalation to abdomen, mid-thorax, upper thorax and reverse for exhalation
		Cat-Cow Marjariyasana/ Bitilasna	From starting position on hands and knees, a fluid alternation between spinal flexion and extension
		Mountain Pose Tadasana	Standing tall with hands at sides and feet hip-width apart
		Partial Sun Salute Surya Namaskar	Standing tall, transition to standing forward bend with knees extended and up to 90° of hip flexion (anteriorly)
	Middle Sequence
		Chair Utkatasana	Standing posture that emulates sitting in a chair, with buttocks leaning against wall, hips flexed to a maximum of 90°(anteriorly) and shoulders flexed to maximum of 180°
		Wall-Plank Chaturanga	A standing push up, done facing a wall; starting position is hands positioned on wall slightly below shoulder height and feet arm’s length from wall
		Tree Vriksasana	A one-legged standing balance; less-weight bearing hip is externally rotated to approximately 45; less-weight bearing foot placed on medial aspect of ankle of the support leg (toes touching ground); chair in front for balance aid
	*picture shows hand at wall rather than on chair	Warrior II Virabhadrasana II	A lateral lunge; forward hip is externally rotated and knee is flexed to approximately 45° (posteriorly); rear hip is internally rotated and rear heel braced against the angle made by the floor-wall; rear foot turned in 30°.  One arm placed on chair for balance and other arm abducted to a maximum of 90°, with shoulder in neutral rotation
		Warrior I Virabhadrasana I	A forward lunge; forward knee is flexed to approximately 45° (posteriorly); rear heel braced against the angle made by the junction of the floor and wall; rear foot turned in 30; one arm flexed at the shoulder  to a maximum of 180° with shoulder in external rotation; other arm placed on chair for balance
		Downward Facing Dog Adho Mukha Svanasana	A standing forward bend; feet hip-width apart and hip flexion to a maximum of 90° (anteriorly) with shoulders flexed to a maximum of 180° and hands pressing on wall
		Side Stretch Parsvottanasana	A standing forward bend; feet in semi-tandem position, hip-width apart. As much distance placed between front and rear foot as is comfortable; forward leg hip flexion to a maximum of 90° (anteriorly) and shoulders flexed to a maximum of 180°,  hands pressing on wall
		Chair Twist Bharadvajasana	A seated twist, on a firm chair; feet are planted on ground hip-width apart, thoracic and cervical spine are axially rotated to right and then to left
		Cobra Bhujangasana	A prone back extension; with blanket under hips and lower ribs, palms are pressed to the floor beneath shoulders, elbows are bent, scapulae are retracted and depressed
		Bridge Setu Bhandasana	A recumbent back extension; from a recumbent (supine) position with knees flexed to 45° (posteriorly), torso is elevated as hips are moved into bilateral extension
		Abdominal Cultivation N/A	A recumbent abdominal strengthening position; starting with hips flexed to 90° (anteriorly) and knees flexed to 90° (posteriorly), hips are alternately extended to a maximum of 120° (anteriorly); neutral spine is maintained
Finishing Postures
		Supine Pigeon Supta Kapotasana	A recumbent posture with bilateral hips, knees and ankles flexed; one leg remains neutral with knee flexed to 45°(posteriorly) and foot pressed into floor; hip of the opposite leg in external rotation to a maximum of 45°, knee flexed to a maximum of 90° (posteriorly) and ankle flexed to 90° resting on the knee of the supporting leg
		Simple Reclining Twist Supta Ardha Jathara Parivarttanasana	A recumbent twisting posture; starting with arms in abduction, shoulders in external rotation, feet next to each other and knees flexed to a maximum of 45° (posteriorly); shoulders are maintained on floor, pelvis and lumbar spine are slowly rotated so that knees fall together towards the right; asana is repeated to left.
		Corpse pose Savasana	Recumbent complete relaxation, with normal breathing

Table 1: Yoga Empowers Seniors Study, Asana Series I.

YESS series I

The middle sequence postures for Series I (English names) were: Chair, Wall Plank, Tree, Warrior II, Warrior I, Downward Facing Dog, Side Stretch, Chair Twist, Cobra, Bridge and Abdominal Cultivation. Table 1 illustrates the YESS senior-adaptation of each posture. The main ways in which our senior adaptations differed from the “standard” asanas, and rationale for these adaptations, are enumerated next. Chair was done at the wall for support and with a yoga block between the knees to enhance alignment. Plank, customarily done on the floor, was practiced at the wall to lessen the upper extremity load. Tree was done with hands on the wall for support and with the foot of the flexed leg bearing partial weight. In Warrior II and Warrior I, a chair was used to assist balance and the rear foot was braced against the wall-floor junction for added stability. Downward Facing Dog and Side Stretch were practiced with the hands placed on the wall, to lessen upper extremity loading and reduce demands on hamstring flexibility and balance. A seated twist (Chair Twist) was done in the chair rather than on the floor to allow participants to use the back of the chair as a lever and to lessen hamstring and hip flexibility requisites. The pelvis was padded in Cobra pose in an attempt to counter excessive lumbar lordosis. Bridge was done in a neutral, rather than extended, spine position. Abdominal Cultivation (not a classical asana) consisted of extensions, but knees were maintained in a flexed position to minimize lumbar loading.

Illustration of Posture	English Name Sanskrit Name	Description of pose
Opening Postures
	Crossed legs on floor Sukhasana	A seated posture on the floor, with back leaning against a wall, legs crossed at the mid-shins, blankets underneath hips and blocks underneath knees for support
	Seated Twist on floor Parivrtta Sukhasana	A cross-legged seated posture, on floor; thoracic and cervical spine are axially rotated to the right and then to left, using one hand on knee and one hand on floor to assist rotation
	Cat-cow, seated Marjariyasana/ Bitilasna	A seated posture in chair, sitting tall with hands on knees; fluid alternation between spinal extension and flexion
	Mountain Pose Tadasana	Standing tall with hands at sides and feet hip width apart
	Partial Sun Salute Surya Namaskar	Standing tall, transition to standing forward bend with knees extended and up to 90° of hip flexion (anteriorly)
Middle Sequence
		Chair Utkatasana		A standing posture that emulates sitting in a chair, hips flexed to a maximum of 90° (anteriorly) and shoulders flexed to maximum of 180° Advancement from series I:  no support from the wall
		Tree Vriksasana		A one-legged standing balance, with non-weight bearing hip externally rotated to approximately 45° Advancement from Series I:  non-weight bearing foot placed on medial ankle of the support leg; only stand on one leg and no use of external chair support (if feasible)
		Warrior II Virabhadrasana II		A lateral lunge, with forward hip externally rotated and knee flexed to approximately 45° (posteriorly); rear hip is internally rotated, rear foot turned in 30°  Advancement from Series 1: Both arms abducted to 90°, with shoulders in neutral rotation; rear foot not braced against the angle made by the junction of the floor and wall
		Wall-Plank Chaturanga		A standing pushup, facing the wall Advancement from Series 1:  hands placed more caudally, mid-way between shoulders and waist; feet placed farther from wall, approximately 6 inches more than arm’s distance
		One-Legged Balance Utthita Hasta Padangusthasana		A single-leg stand with back resting on wall for support; non-support leg knee flexed to 90° (posteriorly), hip flexed to 90° (anteriorly) and foot pressed into block;  shoulders flexed to a maximum of 180°
		Crescent Ashta Chandrasana		A forward lunge, with heel braced against the wall, front knee flexed to a maximum of 90° and rear hip and knee extended; both shoulders flexed to a maximum of 180°, with external rotation
		Side Stretch Utthita Parsvottanasana		A standing forward bend, with feet in semi-tandem position, hip-width apart. As much distance placed between front and rear foot as is comfortable  Modification from Series I:  hands placed on back of a chair; flex shoulders and slide chair away until anterior hip is flexed to a maximum of 90° (anteriorly); neutral spine is maintained
		Chair Twist Bharadvajasana		A seated twist, on a firm chair; feet are planted on ground hip-width apart, thoracic and cervical spine are axially rotated to right and then to left
		Cobra Bhujangasana		A prone back extension; with blanket under hips and lower ribs, palms are pressed to the floor beneath shoulders, elbows are bent, scapulae are retracted and depressed Advancement from Series 1: Hand position placed lower, at approximately mid-thorax
		Recumbent Leg Stretch Supta Padangusthasana		A recumbent hip flexion posture; extended right leg is flexed at the hip to a maximum of 90° (anteriorly) while the other leg remains extended and pressing into the floor; repeat on opposite side (Yoga strap is used on flexed leg)
		Bridge, with hip flexion Salamba Eka Pada Setu Bandha		A recumbent back extension and hip flexion; from a recumbent (supine) position with knees flexed to 45° (posteriorly), torso is elevated as hips are moved into bilateral extension   Advancement from Series 1:  After bilateral hip extension is attained, right hip is moved into 90° of flexion (anteriorly) with right knee flexed to 90°. Pelvis is maintained stable. Repeat on left side
		Abdominal Cultivation Supta Pada Sanchalasana		A recumbent abdominal strengthening position; bilateral hips and knees are flexed to 90°, and feet are off of the floor.  Then hips are extended to a maximum of approximately 120° (anteriorly); extension and flexion of hips are alternated
Finishing Postures
	Hip Flexor Stretch Supta Saithalyasana		A recumbent twist; starting posture is arms in abduction, shoulders in external rotation, feet mat-width apart, and knees flexed to 45° (posteriorly); then knees are allowed to slowly drop toward the right.  A blanket or block support is used under knees as needed.
	Wide-legged Seated Forward Bend Upavishta Konasana		A seated forward bend on the floor; forehead rests on chair, hips are at 90° of flexion (anteriorly) and legs are in abduction (approximately 45°).  Blankets are used underneath hips and forehead and blocks are used  underneath knees for support as needed
	Corpse pose Savasana		Recumbent complete relaxation with normal breathing

Table 2: Yoga Empowers Seniors Study, Asana Series II.

YESS series II

The middle sequence postures for Series II were: Chair, Wall Plank, Tree, Warrior II, Crescent, One-Legged Balance, Side Stretch, Chair Twist, Recumbent Leg Stretch, Bridge and Abdominal Cultivation. An illustration and description of each is provided in Table 2. For the postures that were already taught in Series I, we provided more advanced versions. Chair and Warrior II were progressed to standard versions. For the remainder of Series II, the ways in which our senior adaptations differed from the standard versions of the asanas, and/or the ways in which we advanced already-taught poses to more challenging senior versions, are described next. Plank was still practiced at the wall, but the hands were placed more towards the waist and the feet placed farther from the wall, to increase the upper extremity loading compared to the Series I version. Tree was again practiced with hands on the wall for support, but the contralateral foot was placed on the opposite leg, to increase the work of the weight bearing limb; if possible, we allowed participants to progress to a single-leg tree without use of the wall, to further train balance. Crescent was newly introduced in Series II, with a chair to assist balance and the rear foot braced against the wall-floor junction for added stability. One-Legged Balance was another new pose, done against the wall to aid balance. Participants progressed through 3 versions of One Legged Balance: partial weight bearing of the lifted leg (knee flexed) with the lifted foot placed on blocks; partial weight bearing of the straight, lifted leg, allowing it to rest on a chair; and finally a single leg stand with a straight, lifted, unsupported leg. Side Stretch was advanced by placing the hands on a chair seat. Chair Twist was unaltered from Series I. Recumbent Leg Stretch was new to Series II; a strap was employed to lessen hamstring flexibility requirements. Bridge was advanced by lifting one leg. Abdominal Cultivation was advanced by using leg single alternating leg extensions.

Table 3: Yoga Empowers Seniors Study: Frequency of Performance of each Middle Sequence Pose.

Table 4:Yoga Empowers Seniors Study: Modifications of Asanas for Persons with Physical Limitations, by Body Region.

Consistent exposure to postures

To assure that participants received equal exposure to the asanas, and that none was missed for too many weeks, we specified that no middle series posture could be skipped for more than 3 consecutive weeks. The teaching assistant recorded all postures performed in each class. Table 3 summarizes the percent of classes in which each posture was done and the maximum numbers of skipped weeks for each, demonstrating that we met our goal.

Highlighted teaching

By requiring that only 9 middle sequence postures were done in each class, we freed time for highlighted teaching exercises using props and hands-on cues, which may be especially important to senior students. Props and tactile cues provide exteroceptive cues which assist in accomplishing proper alignment. These augmentation techniques were employed in highlighted teaching exercises for many of the middle sequence poses.

Additional modifications for physical limitations

Although we used senior-adapted asanas, intended to fit the capabilities of community-dwelling older persons, many participants had physical limitations that required further modifications of the senior-adapted postures. We believe that the limitations we encountered are characteristic of the ambulatory senior population in general, as most stemmed from common chronic diseases (e.g., knee and spine osteoarthritis) or pre-existing injuries (e.g., chronic rotator cuff tears).

Many of the postures have movements in common. For example, neck flexion, extension or rotation is components of Cat/Cow, Cobra, Warrior II, Seated Twist and Simple Reclining Twist poses. Organized by affected body region (e.g., neck, low back, shoulder, etc), we catalogue the additional modifications that might be necessary for each posture (Table 4). These modifications were instructed uniformly during the course of YESS.

The Yoga Empowers Seniors Study was an intervention development study, designed to quantify and rank the physical demands associated with the performance of 2 specified series of senior-adapted asanas. This manuscript presents descriptions of the asanas included in YESS and the additional modifications provided for participants with physical limitations.

The Yoga Empowers Seniors Study was an intervention development study, designed to quantify and rank the physical demands associated with the performance of 2 specified series of senior-adapted asanas. This manuscript presents descriptions of the asanas included in YESS and the additional modifications provided for participants with physical limitations.

We undertook this detailed description of the YESS series because we believe that explaining exactly how asanas were done is a critical element of reporting yoga research. Without a detailed description of the postures and sequencing, study results (in this case, the biomechanical, functional and side-effect outcomes) cannot be interpreted. This reporting requisite is especially relevant if the asanas were tailored to meet the needs of a particular population, such as seniors: the more customized the postures, the greater the need for precise descriptions of what was actually taught. We acknowledge our own prior shortcomings in this arena, having instructed approximately 75 pose variations in the Yoga for Kyphosis Study but not having provided a detailed explanation of each [4]. Similarly, precise explanations of each asana are absent from several studies [7-9]. While others have not published manuscripts containing details of their entire series, they offer training (Silver Yoga Exercises) or have a manual available for purchase (yoga for chronic low back pain) [10-15].

We used a standardized intervention—the same series was done in each class. We acknowledge the tension between a set series and one that varies from class-to-class. In research, a uniform intervention enhances reproducibility; more clearly characterizes the treatment “dose” and is more aligned with principles of trial design because it maximizes treatment homogeneity. In multi-site studies, a uniform series makes it easier to train teachers, to monitor protocol fidelity and to minimize inter-teacher variation. A uniform intervention is also well-suited to dissemination because it can be well described and replicated. However, the repetition of a standardized series may be tedious to some, requires a reasonably homogenous population that is well-matched to the circumscribed series and does not allow the teacher to add new poses or progress to advanced variations (beyond those in the series) for those individuals who are developing at a faster pace than their counterparts.

In summary, the YESS research team’s overarching research mission is to develop a safe, effective and portable yoga program for seniors. We are implementing this research goal in a series of measured steps, the first of which is the intervention development study, the design of which is reported here. The intervention development study set out to rigorously examine the biomechanical characteristics, physical performance effects and side-effect profiles of 24 Yoga postures. This report gives the rationale underlying the YESS asana series, describes each posture, the order of postures within series and how asanas were advanced from Series I to II. This accounting will enable the yoga research and teaching communities to comprehend exactly how the yoga intervention was delivered, which is critical to the interpretation of the biomechanics, physical performance and side effects outcomes of YESS.

The authors thank the women and men who generously gave of their time to volunteer for the YESS project. YESS was supported by Grant Numbers RO1 AT004869G (National Center for Complementary and Alternative Medicine) and P30AG028748 (National Institute on Aging). The content of this report is solely the responsibility of the authors.