Biomechanical Analysis of Lower Limb in Bharatanatyam Dance Using Musculoskeletal Modeling

Abstract

Background:

Bharatanatyam, a classical Indian dance form, involves dynamic lower limb movements often performed in extreme joint positions. This study aims to biomechanically evaluate one of the basic movement units (adavu) of Bharatanatyam called Paichal adavu and its three variations, denoted for this study as Simple Paichal (SP), Paichal Variation (PV), and Paichal Mandi (PM), using 3D motion capture and musculoskeletal modeling.

Methods and Materials:

A trained male Bharatanatyam dancer performed the three variations of the Paichal movement in a motion capture lab equipped with a Qualisys motion capture system and an AMTI force plate. Kinematics, joint contact forces, muscle activations, and muscle forces were analyzed using a musculoskeletal model.

Results:

The PM showed the highest compressive knee joint force (16 BW) and maximum muscle force (10 BW in the vastus lateralis), indicating high stabilizing demands. The PV exhibited the highest hip flexion (112.4°) and ankle dorsiflexion (–33°), along with substantial joint forces, reflecting dynamic loading. The SP had the lowest overall joint and muscle loads but showed short bursts of muscle activation, especially in the rectus femoris and tensor fasciae latae (TFL).

Conclusion:

Among the analyzed movements, PM imposed the greatest muscular and joint stabilization demands, while the PV, with body turn, involved the highest mobility and dynamic loading. These biomechanical insights can support the development of safer techniques and, thus, injury prevention for Bharatanatyam dancers.

INTRODUCTION

Bharatanatyam is one of India’s most ancient and culturally rich classical dance forms, with an extensive movement vocabulary. The movements demand complex coordination of body parts in rhythm and expression. They enhance the symmetrical construct of the body, involving squats and dynamic transitions with jumps and spins. These movements can place significant biomechanical loads on the lower limbs, especially at the hip, knee, and ankle joints, often requiring extreme ranges of motion and sustained muscle effort.

The classic basic stance in Bharatanatyam is the outward flexed knee position called Araimandi, like the Demi-plié of Western classical ballet. Almost all basic movement units or adavus in Bharatanatyam use this flexed knee position of Araimandi. The adavus are the building blocks of the vocabulary of Bharatanatyam. Some adavus use the squat position, mandi, some the stamping of feet, and some involve body jumps while maintaining the flexed knee position. The latter is called the Paichal Adavu. It is a foundational step that builds stamina and body control. It involves dynamic lower limb movements with extreme joint positions.

There are three variations of the Paichal Adavu. Simple Paichal (SP) involves jumping to the sides in a flexed knee position and landing on one foot, placing the other foot sequentially behind the landed foot. Ground reaction forces for the landing of the first foot were recorded. In the Paichal Variation (PV), the jump from the Araimandi static position is executed by lifting one foot to displace the other, combined with a quick body turn. The displaced foot immediately stretches backward, and the final position ends with the body facing sideways, the landed foot on the ground, and the displaced foot resting on its forepart. The landing foot forces after the jump and turn were recorded. Paichal Mandi (PM) involves lifting one foot from the Araimandi position to execute the jump that propels the body forward or diagonally, moving toward a full Mandi posture akin to a squat. In this case, the landing force of the first foot initiating the Mandi movement was recorded.

Dancers are increasingly being recognized today as performing athletes facing the high risk of musculoskeletal injuries. Studies have shown that over 70% of Bharatanatyam dancers report injuries during their careers, with the low back, knee, and ankle being the most commonly affected regions.[1] These injuries are often attributed to repetitive strain, extreme joint positions, inadequate strength or flexibility, and improper technique. A study specifically identified the position of Araimandi (the basic stance in Bharata Natyam) along with Natyarambham (the basic hand extension posture) held for prolonged durations as high-risk, emphasizing the importance of biomechanical evaluation for injury prevention.[2]

Despite its physical intensity, Bharatanatyam remains underrepresented in biomechanical research compared to Western dance. Existing literature highlights the need for an objective, movement-based analysis to better understand performance demands. While studies have explored joint pain prevalence, joint flexibility, and strength in dancers vs. non-dancers,[3] few have employed 3D motion capture and musculoskeletal modeling to examine how specific dance movements can affect joint angles, forces, and muscle activity, especially across different skill levels. While previous studies have reported the prevalence of musculoskeletal pain among Bharatanatyam dancers,[1] and others have analyzed posture using static photogrammetry,[4] detailed biomechanical modeling of dance movements remains limited. Additionally, biomechanical studies on Western dance forms like ballet and tap have used inverse dynamics but not full musculoskeletal modelling.[5] A similar methodology has previously been applied to Irish dance, where 3-D motion capture, force-plate data, and a segment musculoskeletal model were used to calculate muscle loading and ankle joint contact forces during the Rock step.[6]

Biomechanics offers valuable tools for such analyses. Motion capture systems are widely used to quantify the dynamics of human movement by capturing precise body segment motions.[7] When combined with musculoskeletal modeling, they enable the estimation of internal forces such as muscle forces and joint contact forces during various activities, using motion capture and force plate data as input.[8,9] To the authors’ knowledge, this is the first study to combine 3D motion capture, force plate data, and OpenSim modeling to estimate joint contact forces and muscle forces during specific Bharatanatyam steps, providing a novel perspective on the internal loading and movement demands of this classical dance form.

Thus, this study aims to analyze the kinematics and kinetics of a selected Bharatanatyam basic movement unit, the Paichal Adavu, and its variations using biomechanical modeling. The findings can help provide insight into the movement complexity and loading patterns of each posture, supporting injury prevention, technique refinement, and scientifically informed dance pedagogy.

MATERIALS AND METHODS

Participant

One young, healthy, trained male Bharatanatyam dancer (weight: 44 kg, age: 25 years) participated in this study. The participant had no recent history of musculoskeletal injuries and provided written informed consent. The institutional ethics committee approved the study.

Data collection

The dancer performed the three variations of the foundational step of Bharatanatyam called Paichal adavu, designated as SP, PV, and PM is in a biomechanics laboratory [Figure 1]. Data collection utilized a 12-camera Qualisys® 3D Motion Capture System operating at 300 Hz (Qualisys AB, Göteborg, Sweden). Ground reaction forces (GRF) were recorded at 1200 Hz using an AMTI force plate. A Baker’s 36-marker set[10] was placed on anatomical landmarks to enable accurate tracking of lower body kinematics.

Figure 1.

Dancer performing the dance step (a) Simple Paichal (SP) (b) Paichal Variation (PV) (c) Paichal Mandi (PM)

Musculoskeletal modeling and analysis

Kinematic and kinetic data were processed in OpenSim 4.2,[11] an open-source musculoskeletal modeling software. A generic Catelli[12] model was scaled to the participant’s anthropometry by using static trial data. Analysis was performed for the right dominant leg only. Inverse kinematics to compute joint angles, Inverse dynamics to calculate net joint moments, Static optimization to estimate muscle activations and muscle forces, joint reaction analysis to compute joint contact forces at the hip, knee, and ankle in superior (compressive), anterior, and medial directions.

Data processing

Each movement trial was segmented and time-normalized to 100% of the movement. Muscle forces and joint contact forces were normalized to body weight. MATLAB was used to process the output data and generate graphical representations.

RESULTS

Joint kinematics

Among the three postures analyzed were SP, PV, and PM, distinct differences in joint kinematics were observed [Figure 2].

Figure 2.

Comparison of joint kinematics

The hip flexion angle reached a maximum of 112.4° in the PV posture, compared to 74.4° in SP and 69.8° in PM, indicating a substantially higher mobility demand. Similarly, the pelvis list increased sharply to 33° in PV, versus only 6.8° in SP, suggesting significant lateral trunk involvement or asymmetry during the movement. Knee flexion was the highest in PM (128°), reflecting deep joint bending typical of this step. Additionally, ankle dorsiflexion was greatest in PV (–33°), implying increased demand on ankle mobility and balance control during dynamic execution.

These differences in joint angles highlight the increased biomechanical complexity and joint loading during PV movements.

Muscle activation

Figure 3 shows muscle activation patterns for the three different movements. The PM showed the highest and most sustained muscle activations, especially in the quadriceps group (vastus lateralis, medialis, intermedius), soleus, and tibialis posterior, reflecting the need for strong lower limb support during deep flexion. The PV had moderate activations spread across multiple muscles, including rectus femoris, psoas, iliacus, and tibialis anterior, indicating balanced control and upright movement. The SP showed brief and sharp activations, mainly in rectus femoris, TFL, and biceps femoris short head, consistent with quick, dynamic motion and lower muscular demand overall.

Figure 3.

Comparison of muscle activations

Muscle forces

Muscle force analysis revealed distinct patterns across the three Paichal movements, with specific muscles contributing differently to each movement [Figure 4].

Figure 4.

Comparison of muscle forces

The PM showed the highest muscle forces overall, with a peak of 10 BW in vastus lateralis, followed by 5.5 BW in soleus, 2.9 BW in vastus medialis, and 1.8 BW in tibialis posterior. These high force levels in the quadriceps and calf muscles reflect the muscular effort needed to maintain and rise from deep joint positions. Additionally, moderate forces were observed in the gluteus maximus 3 (1 BW) and psoas (1 BW), indicating significant hip stabilization.

The PV showed slightly lower but still high forces, especially in vastus lateralis (9.9 BW), tibialis posterior (4.4 BW), vastus medialis (3.4 BW), and soleus (3.3 BW). This indicates that the variation step involves considerable muscular effort, particularly in the quadriceps and ankle stabilizers, although not as much as in the PM.

In contrast, the SP generated lower peak muscle forces overall, with the highest values being 4.2 BW in vastus lateralis, 3.7 BW in soleus, 2.6 BW in tibialis posterior, and 2.5 BW in rectus femoris. Most other muscles remained below 1 BW, indicating that in this movement, there is comparatively less demand in terms of muscular force, though it still requires dynamic control from selective muscles, especially in the lower leg and anterior thigh.

Joint contact forces

Peak joint contact forces revealed clear differences between the three movements [Figure 5]. The PM showed the highest overall loading, with a maximum superior (compressive) force of 16 BW at the knee, the highest observed in the analysis. It also demonstrated elevated medial forces at the hip (1.9 BW) and knee (2.6 BW) and the highest anterior force at the ankle (3.7 BW), indicating strong multi-directional loading and stabilization demand during deep postures.

Figure 5.

Comparison of joint contact forces

The PV showed the second-highest compressive forces with 13 BW at the knee and 11 BW at the ankle. It also had a substantial anterior force at the knee (7.8 BW) and moderate medial forces reflecting a high but more balanced load distribution.

The SP had the lowest joint contact forces overall, with anterior forces below 1 BW and superior forces of 5 BW (hip), 8.2 BW (knee), and 9.6 BW (ankle). Medial forces remained under 1 BW, suggesting lower mechanical demand consistent with its brief and dynamic movement profile.

DISCUSSION

The biomechanical findings of this study revealed distinct kinematic and kinetic demands in the execution of the basic movement unit of Paichal adavu and its variations. The PM produced the highest compressive forces at the knee joint (16 BW) and required strong activation and force output from the quadriceps and ankle stabilizers. This movement towards getting into a squat demands continuous muscular support, particularly from the vastus lateralis, soleus, and tibialis posterior.

In contrast, the PV demonstrated extreme joint angles, especially in the hip (112.4° flexion) and ankle (–33° dorsiflexion), along with high anterior knee loading (7.8 BW) and substantial muscle forces across hip flexors and dorsiflexors. These results suggest this movement presents the greater mobility challenge and dynamic control requirement, especially for balance and transition movements.

The SP, although biomechanically least demanding in terms of joint contact forces and peak muscle forces, involved brief and sharp muscle activations in selective muscles such as rectus femoris, TFL, and biceps femoris short head. This aligns with the quick directional change pattern of this movement, indicating coordination-focused neuromuscular demands rather than sustained load.

These biomechanical findings align with injury prevalence reports by Nair et al.,[1] which identified the knee and ankle as the most commonly injured joints in Bharatanatyam dancers, supporting the clinical relevance of the high joint loads observed in this study. Additionally, Nair et al.[1] also noted frequent muscle soreness in the thighs and calves, which supports the high muscle activations and forces observed in the quadriceps and calf muscles during the Sitting and Variation steps in this study. These distinctions are important because different movements load the musculoskeletal system in unique ways. Excessive repetition of the PM movement may contribute to overuse conditions at the knee or ankle, while PV movement may predispose dancers to flexibility-related injuries or joint stress under fatigue. For beginners or those with compromised strength, improper execution may increase injury risk. Compared to the Irish dance study which reported ankle joint contact forces up to 14 times body weight,[6] the present Bharatanatyam study observed even higher joint loading at the knee up to 16 BW during the PM step, indicating that certain classical Indian dance movements may impose equal or greater mechanical stress than high-impact steps in Western dance forms.

This analysis thus supports integrating biomechanical insights into the Bharatanatyam pedagogy, encouraging movement selection and training volume to be based not only on choreographic design but also on mechanical demand and injury risk. To reduce injury risk in Bharatanatyam, dancers should approach each step with targeted strategies. The PM step, with its high joint and muscle loading, requires strong quadriceps and ankle stabilizers, along with limits on repetition and proper recovery. For the PV, which demands extreme mobility and balance, flexibility training and dynamic control exercises are essential. The SP, while lower in load, involves rapid muscle activation and benefits from coordination and stability training. Injury prevention in Bharatanatyam should include strength training for key muscles such as the quadriceps, calf muscles, hip stabilizers, and core muscles, to support joint loading and posture. Mobility exercises should target the hip flexors, ankles, and hamstrings to allow safe execution of deep and dynamic movements. Additionally, movement quality drills that enhance balance, coordination, and neuromuscular control, especially for landing and directional transitions, are essential for reducing injury risk and improving performance across all Bharatanatyam steps. The knee and ankle joints emerged as the most mechanically loaded and potentially injury-prone regions, particularly during the Sitting and Variation steps, due to the high compressive and anterior forces, highlighting the need for targeted strengthening and control strategies.

This study involved only one trained male dancer, limiting generalizability to a broader population. Marker-based motion capture is prone to soft-tissue artefact and placement errors, potentially affecting kinematic accuracy. The musculoskeletal model used constrained the knee to a single degree of freedom and lacked subject-specific joint mechanics. Only the dominant leg was analyzed, omitting bilateral movement patterns. Muscle forces were estimated using static optimization without Electromyography (EMG) validation, and all movements were performed in a lab setting, which may not fully replicate stage conditions. These factors should be considered when interpreting the findings. Future studies can focus on investigating the role of the non-dominant limb, particularly examining whether it experiences higher joint compression forces, altered muscle activation patterns, and increased susceptibility to injury. Additionally, future work may compare kinetics and kinematics between male and female dancers, as well as between well-trained and beginner-level dancers, to provide a more comprehensive understanding of performance and injury risk.

CONCLUSION

This study quantitatively compared the joint angles, muscle activations, muscle forces, and joint contact forces associated with three variations of a foundational Bharatanatyam movement, the Paichal adavu. The findings highlight that the PM imposes the highest mechanical demands on the lower limb due to large muscle forces and joint loading. The PV requires significant joint mobility and dynamic control, and the SP, though less force-intensive, challenges coordination through brief, high-muscle-activation periods. These results offer biomechanical evidence to guide injury prevention, rehabilitation, and incorporate scientifically informed training in the classical Indian dance form of Bharatanatyam. The findings reinforce that the knee and ankle joints, along with lower limb muscles such as the quadriceps and calf group, are key sites of stress, highlighting the need for targeted strength training and injury prevention strategies in Bharatanatyam practice. Further studies with more participants and variations in skill level can help expand these findings. In the context of Bharatanatyam’s 2000-year-old tradition, it is important to recognize that modern dancers may not possess the same physical conditioning as earlier generations, owing to lifestyle changes and reduced daily physical activity. As a result, the biomechanical complexity of traditional movements such as mandi adavu involving deep knee flexion may pose greater physical strain today. This study’s findings support the growing trend of modifying or reducing such movements in practice. Therefore, it may be necessary to rethink dance pedagogy by incorporating pre-training evaluations, core strengthening, and structured progression, ensuring that learning remains safe, sustainable, and faithful to the artform.

Ethical clearance

The research was conducted in accordance with the principles of the Declaration of Helsinki for studies involving human participants. Ethical approval was obtained from the Institutional Ethics Committee of K. J. Somaiya College of Physiotherapy, Mumbai (Ref. No: KJSCPT/1162-A/23-24).

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.