BIOMECHANICS OF ARCHERY

Archery can be described as a comparatively static sport requiring strength and endurance of the upper body, in particular the forearm and shoulder girdle. Skill in archery is defined as the ability to shoot an arrow to a given target in a certain time span with accuracy. According to large number of shots undertaken in one competition, the shooting movement of the archer is required to be well balance and highly reproducible”. Nishizono et al., (1987) divided these phases into six: bow hold, drawing, full draw, aiming, release and follow-through. Each of these phases represented a stable sequence of movements and was ideal for studying the motor control and skill acquired during this voluntary kinematic process. Additionally, skill in archery directly depends on interaction between the subject, the bow and the arrow during executing the shot, and both training and competition do demand a certain extent of long hours of concentration with some physical ability such as strength, endurance, and postural fine control.

Biomechanics of Bow Hand:

It is very important for an archer to have a complete control on his/her bow hand during aiming phase. Regarding this fact, Roland et al.,(2011) present some technique to prevent control problem and according to Ganter et al., (2010) it is believed that to achieve best control on the bow, the critical point for archers is to use bones, not muscles. The archer must consider how to structure a shooting technique to maximize the use of bones and minimize the use of muscles, because bones don’t get tired yet muscles most certainly fatigue. Consistency in archery shooting depends on adopting a posture in which forces between the archer and bow are correctly aligned. Muscles play an important role maintaining the correct posture and `releasing the arrow. The utilization of bigger proximal muscles is thought to promote consistency due to the higher tolerance for fatigue than the smaller distal muscles. Many researches in biomechanics of archery have described the different coordination and muscular activation patterns in archers by EMG during the releasing phase.

According to motion analysis studies, posture of archer's arms (both Bow Hand/Arm and Drawing Hand/Arm) is the main factor affecting length of moment arm and therefore magnitude of exerted moment to the bow wrist. The results reveal that the archers who experiments more amount of moment in their bow wrist during aiming phase by keeping hyperextended and ulnar deviated wrist, in hence needs more activity in their wrist and forearm muscles to hold the bow in a fixed appropriate position and bearing this load is not possible for more than few moments, the archer has to release the arrow as soon as possible. Results, less time for aiming and less accuracy to hit a better score. So an archer's skill level directly affects his/her ability to control the bow during aiming phase.

The bow shoulder position must be stable, easy to maintain and repeatable from shot to shot. The easiest position is to drop the shoulder onto the “collar bone”, the lowest it can go is when the collar bone is sitting on the ribs.

Biomechanics of Drawing Hand:

The line of force (bow weight) should pass through the bow hand, to the drawing hand and the drawing elbow, this is particularly important. If the line of force does not go through the drawing elbow you must use your drawing arm Biceps or Triceps to hold back the weight of the bow.

After you set the hook and grip, look up, prepare your torso, and confirm that your stance and posture are correct. Set your head position and shoulder alignment so that your shoulder is approximately 60 to 80 percent in line with the target. Your head should sit over the ball of your back foot (On Heel), thus helping to provide the 60/40 ratio of weight distribution on the balls of your feet, and must not sit over your spine, helping you to maintain a flat back and some tension in your lower abdominal muscles. It is also important that you feel a small amount of tension in the lower trapezius at the final set position.

The important point to note is the shoulder has a wide range of movement and to minimize the use of these muscles around the shoulder must be as low as possible. The lower we get the shoulder the more lined up the bones will be. If a person has their shoulder pushed in as far as possible toward the arrow the natural reaction is for the drawing shoulder to move back away from the body, this then gives a straight line between both shoulder joints, the bow arm elbow and bow wrist and requires minimum use of muscles.

With the repetitive motion, an archer is susceptible to numerous injuries.

In recent years Physiotherapy has evolved beyond the Post injury intervention to Preventive Intervention where we can prevent many injuries by train particular muscles, which are extensively used in Archery. And by having a amazing concept “Stabilize the proximal and Mobilize the Distal” Stabilizing the Spinal core Muscles is very important and beneficial. Lumbar Core Set, Triceps of Bow Hand and Latissimus dorsi are main Stabilizers and Mid Thoracic muscles (Lower Trapezius and other Retractors of Scapula) and Biceps of Drawing Hand are main Mobilizers in Archery.

Research Support:

1) Paul, Maman, Sathiyaseelan Ganesan, and Jaspal Singh Sandhu. "Effect of sensory motor rhythm neurofeedback on psycho-physiological, electro-encephalographic measures and performance of archery players." Ibnosina Journal of Medicine and Biomedical Sciences 4.2 (2011): 32-39.

Abstract: Neuro feedback is an effective tool in sports psychology to train athletes to enhance performance levels. Archery players are required to concentrate on accuracy during archery performances, which tends to be attained by a peak sensory motor rhythm of the electroencephalography component. The selected subjects of university level archery players have intervened with neurofeedback for four weeks. Measurements were taken to find the effect of neurofeedback training (NFT) on heart rate deceleration, precompetition pleasure level, post-competition pleasure level, pre-competition arousal level, post-competition arousal level, performance level, precision, sensory motor rhthm (SMR)/ theta ratio and SMR epoch mean of archers during competition. Statistical analysis reveals that pre-competition pleasure level (p< 0.05), pre-competition arousal level (p< 0.05), post-competition arousal level (p< 0.01) and SMR/ theta ratio (p< 0.05) showed statistically significant changes [deleted after the effective twelve sessions of SMR neurofeedback training] in the experimental group but not the control group. After twelve sessions of NFT training the experimental group archers were able to regulate the psychological status and EEG components during archery performance. The result of the present study suggests that neurofeedback training improves the archery players’ regularity in scoring by enhancing accurate arrow shoot attained by controlling and regulating psycho-physiological and electro-encephalographic measures.

2) Grover, Jasleen Kaur, and Akhoury Gourang Kumar Sinha. "Prevalence of Shoulder Pain in Competitive Archery." Asian Journal of Sports Medicine 8.1 (2017).

Background: Studies reporting prevalence of shoulder pain in competitive archery are limited. The purpose of this study was to document the features of shoulder injuries and determine the prevalence of shoulder pain in Indian competitive archers.

Methods: A cross sectional survey of 156 archers (M = 91, F = 65) mean age = 20.27_2.31 (range 15 - 28 years) was conducted during All India Inter University Archery Tournament 2013. Study consisted of two parts - schedule interview and clinical examination of both shoulders. t test, odds ratio and cross tabulation with chi square (_2) test were the tool of statistical analysis.

Results: The point and lifetime prevalence of shoulder pain was 54.4 %.( n = 85) and 82.69% (n = 129) respectively. 64.74% archers (n = 101) had experienced recurrent shoulder pain. Positive Hawkins- Test (80.00%), Speed’s Test (60.00% ), lift off test (51.76%), painful resisted isometric supraspinatus contraction (58.1%), and apprehension relocation test (42.35%) were common clinical findings observed in archers with current shoulder pain. The Occurrence of current shoulder pain was significantly (P_0.05) associated with previous injury (OR = 2.57) and young age (OR = 2.13) but not with extrinsic risk factors. Shoulder pain interfered with execution of sporting activity in 20% of archers.

Conclusions: Occurrence of shoulder pain in the game of archery is common. Majority of archers with current shoulder pain were found afflicted with overuse injuries affecting supraspinatus, long head of biceps and subscapularis muscle possibly due to secondary impingement.

Common Injuries Include:

Scapular muscle Injuries – The Scapular muscles (muscles that stabilizes the Scapula)
Rotator Cuff and Scapular muscle Injuries – The rotator cuff (muscles that stabilizes the shoulder) injury is caused by poor shooting mechanics.
Tendonitis – Caused by the overuse of muscles and tendons in the arm, elbow and wrist.

References:

Azadeh Kian, et,al. Comparing the ability of controlling the bow hand during aiming phase between two elite and beginner female compound archers: A case study. European Journal of Experimental Biology, 2013, 3(4):103-111
Cevdet Tinazci. Shooting dynamics in archery: A multidimensional analysis from drawing to releasing in male archers. Procedia Engineering 13 (2011) 290–296
Paul, Maman, Sathiyaseelan Ganesan, and Jaspal Singh Sandhu. "Effect of sensory motor rhythm neurofeedback on psycho-physiological, electro-encephalographic measures and performance of archery players." Ibnosina Journal of Medicine and Biomedical Sciences 4.2 (2011): 32-39.
Grover, Jasleen Kaur, and Akhoury Gourang Kumar Sinha. "Prevalence of Shoulder Pain in Competitive Archery." Asian Journal of Sports Medicine 8.1 (2017).

Dr. Srinivas. P.T (Reg No. L-39682)

Head Of Department (Kaggadasapura branch)

Spectrum Physio Pvt Ltd

Bangalore.