What biomechanics principles are involved in the forehand smash and what is fundamental towards optimizing the badminton smash technique?

Badminton is a net based sport that consists of dynamic, complex and various biomechanical dependent movements. In badminton the forehand smash is a common attacking sequence of movements that requires a strong emphasis on technique and timing. Sakurai and Ohtsuki (2000) showed that the power, precision and speed of the forehand smash are extremely important in getting points to win a game. This is why it is critical to incorporate biomechanical principles to optimise this particular skill. Performing the forehand smash correctly places immense pressure on your opponent to return the shuttle. The forehand smash promotes faster velocity of the shuttle giving less time for the opponent to react, but most importantly is the shuttles angle and trajectory that determine a successful smash. 

The forehand smash contains various elements that are crucial for optimizing the technique.  For an effective forehand smash, biomechanical principles should be considered to each sequence of the skill, such as preparation, back swing, forward swing, impact and follow through. Lees (2003) recognises that in badminton the importance of the wrist flexion, pronation of the forearm and endorotation of the upper arm combined with biomechanical principles can be a powerful tool in badminton. For optimal performance the forehand smash depends on all elements working together and in consecutive order. This blog will highlight the key biomechanical principles for the forehand smash that promotes maximum power and accuracy for successfully finishing the point in badminton. The optimal forehand smash should contact the shuttle at the highest possible point with the angled racket to ensure the sharpest downward trajectory on the opponent’s court. This can be achieved by adapting the biomechanical principles.

Figure 1: Badminton forehand smash sequence. (All Badminton, 2013)

Analysing the forehand smash sequence, various biomechanical principles can be utilised to optimize the skill. The following concepts will be identified in the forehand smash phases:

• Centre of gravity 
• Angular Momentum
• Moment of inertia
• Height of release
• Angle of release
• Projectile and trajectory motion
• Newton's Laws

Step 1: Preparation Phase 

Skill Cues:

• Body should be sideways with non-racket shoulder towards the net in line with the oncoming shuttle.

• Legs should be spread apart to widen the base of support with bent knees to lower the athlete’s centre of gravity.

To create the optimal forehand smash it is vital to start with a solid base of support. This can be achieved by widening the space between the legs with bent knees to lower the athlete’s centre of gravity. Having a supported centre of gravity allows all the particles of the body to be evenly distributed to maximise control of technique (Blazevich, 2012). If an athlete attempts the forehand smash with a poor centre of gravity then most likely will become off balance which can reduce the power and accuracy of the shot and disrupt the overall sequence of the skill.

The diagram shows a wide base of support and a low centre of gravity. This represents optimal preparation as an elite athlete would demonstrate this position with majority of his weight on his racket foot while maintaining balance. Referring to figure 2, the line of gravity falls within the boundaries of the supporting base which ensures that the athlete is relatively stable.

Figure 2: Wide base of support for balance and optimal centre of gravity. (HubPages, 2014)

Step 2: Back swing phase (with jump)

Skill Cues:

• As weight is transferred to the back push your body with the racket foot into the air moving your centre of gravity into position

• Bring your legs to the back to generate more force while suspended in the air at the highest point possible.

• Stretch racket arm as far back as possible to provide optimal momentum for the forward swing.

Newton’s third law states “for every action there is an equal and opposite reaction” (Blazevich, 2012). For the forehand smash, applying a downward force before jumping can accelerate the body forward and upwards if it can overcome inertia. Reaching optimal height when jumping provides a greater trajectory angle when making contact at the highest point with the racket. The back swing of the forehand smash if vital for generating power during the forward swing phase as it stretches as far back behind the athlete to create maximum rotation and force. The more flexible your racket arm can pull back will create the optimal distance for generating greater force.

Step 3: Forward swing phase

Skill Cues:

• Racket and arm should be straight with a slight bend in the elbow to avoid injury.

• The point of impact should be slightly in front of the athlete to maximise the moment of inertia.

Optimal forward swing is dependent on the force generated by the moment of inertia, which produces greater power the further the distance away from the axis (Blazevich, 2012). During the forehand smash the further the racket arm is behind the athlete the more momentum can be generated increasing the power when making contact with the shuttle. The centre of gravity is closer to the body when legs are bent back during the athletes jumping phase. Once the forward swing is in motion, legs should begin to straighten out to return to the optimal line of gravity, while also transferring the power from your legs to the forward swing’s momentum, increasing power.

Force summation is an important biomechanical principle for optimal badminton techniques. When performing the forehand smash it is important to use the largest muscles first, followed by the smallest muscles while sequentially accelerating each body part to maximise momentum (PE studies, n.d.). The more joints involved in the technique will produce greater acceleration and promote optimal forehand smash.

This video highlights force summation during the forehand smash in badminton:

                

        Figure 3: Professional athlete performing the forehand smash. (Joy, 2014)

Step 4: Impact phase

Skill Cues:

• Straightening the elbow when connecting with the shuttle.
• Flexion of the wrist in a downward motion at the point of impact increases the power and angle towards the opponent's court.
• Hitting the sweet spot of the racket to provide better accuracy and power to the smash. 

                    Figure 4: Flight trajectory of forehand smash while jumping and when feet stay sedentary. (Punkh, 2013)

The impact phase of the forehand smash determines the trajectory of the shuttle and the time it would take to reach the destination. For optimal performance the shuttle should make point of contact with the racket at the highest possible point to provide the best possible shot that consists of power and downward trajectory. The angle of release of the shuttle determines how long it will stay airborne and considers how far (horizontally) it will move with gravity as a constant effect (Blazevich, 2012). In badminton the angle of release is important as a downward angle creates less time for the opponent to react and difficulty to return, which is why the height of release can be considered to maximise the success of the shot. Referring to figure 4, steep smash and flat smash display the trajectory of the shuttle once it made contact with the racket. The flat smash is done while the feet stay on the ground and the complete movement transfers from the racket foot to the rotation of the racket arm. The steep smash incorporates a jump technique using the legs as an extra tool for generating force. Comparing both smashes the flat smash has the shuttle airborne for longer, which provides more time for the opponent to return. To increase optimal performance, incorporating a successful jump provides a better angle of release that reduces flight time of the shuttle and a higher level of force is applied. 

Step 5: Follow Through phase

Skill Cues:

• Racket should follow through after making contact with the shuttle to put maximum force into the shot.

• Follow through should lead the racket towards the non-racket leg by crossing the body.

• Landing with slightly bent knees to prevent injury and wide support from legs to ensure balance and stability ready for the return.

The follow through phase is just as important as the impact phase. By having the correct follow through technique after the shuttle has contacted the racket ensures the trajectory will be maintained.  For optimal performance of a skill the technique should be continuous and without a break in action once the racket has connected with the shuttle. If an athlete suddenly stops when making contact with the shuttle then all the generated force has to go somewhere, which can cause injury as body joints and movements naturally move to disperse the built up force. For optimal performance of the forehand smash it is critical that once the racket has made contact with the shuttle it is then swung down and crosses the body to ensure no momentum is lost during the hit. This is supported by referring to Newton’s Law of inertia as “an object will remain at rest or continue to move with constant velocity as long as the net force equals zero” (Blazevich, 2012). This expresses that the ability to stop a moving object to become stationary is difficult due to inertia being a constant factor. Depending on the outcome of the forehand smash the follow through phase provides ample time to receive feedback of the shuttle's position as the movement places the body into a ready position for the oppositions return.

By following the phases of the forehand smash and considering the biomechanical principles, in time and practice your technique could be similar to an elite athlete. Here is a clip of an effective forehand smash:

Figure 5: Professional athlete successfully performing the forehand smash. (Joy, 2014)

The answer

The forehand smash in badminton applies a great amount of pressure towards the opponent in attempting to return the shuttle. If the optimal forehand smash has been executed considering the biomechanics principles then the shot is almost impossible to return. Analysing the various stages of the forehand smash has identified the key biomechanical principles that define an optimal smash in badminton. Starting the skill in a wide balanced body position determines the effectiveness of the smash in relation to the amount of force that can be generated from a strong centre of gravity. Blazevich (2012) also states that the lighter you are the optimal jump height can be reached as we are constantly affected by gravity when moving vertically. Considering optimal performance the physiology of the athlete can have a strong influence in maximising the power and trajectory of the smash, which was seen in most badminton athletes that were tall with a slim build and a good arm length (Ooi et al., 2009). Incorporating the jump during the forehand smash can create a higher contact point with the shuttle that changes the trajectory to a steeper angle causing difficulty for the opponent to return. When making contact with the shuttle, it is critically important that each body segment (force summation) makes optimum contribution at exactly the right time before the following body part begins. By maximising the momentum and force of the skill, optimal forehand smash can be reached when considering all biomechanical principles. This then increases the speed of the shuttle and accuracy to win the point and eventually the game.  

How else can this information be used?

The biomechanical principles for the forehand smash can be incorporated into many other sports other than badminton. Different components of the technique can be used in many other sports. For instance, biomechanical principles relating to base of support and centre of gravity before jumping are used in tennis and basketball, but change slightly with the use of a ball instead of a racket. Developing the skills to effectively perform the forehand smash using various biomechanical principles show athletes with improved accuracy, timing and power, this could be the difference from winning and losing the point. This information would be essential for athletes that want to develop and optimise their forehand smash by gaining an understanding of biomechanical principles in badminton. In schools, coaches and teachers can identify mistakes of students performing the forehand smash by having a basic understanding of biomechanical principles that can correct these mistakes.

References

All Badminton. (2013). Badminton Smash. Retrieved from http://info.allbadminton.net/10769/youtube-badminton-technique-forehand-smash/

Blazevich, A. (2012). Sports Biomechanics the basics: optimising human performance. London: Bloomsbury.

HubPages. (2014). How to hit a Great smash in Badminton. Retrieved from http://badmintondboubles.hubpages.com/hub/Badminton-Smash-How-to-Play-the-Shot

Joy, J. (2014). Badminton Smash Technique (slow motion). Retrieved from https://www.youtube.com/watch?v=gwDNZsEEvJ4

Lees, A. (2003). Science and the major racket sports: a review. Journal of sports sciences, 21(9), 707-732. 

Ooi, H., Tan, A., Ahmad, A., Kwong, W., Sompong, R., Mohd Ghazali, A., ...& Thompson, W. (2009). Physiological characteristics of elite and sub-elite badminton players. Journal of sports sciences, 27(14), 1591-1599.

PE studies. (n.d.). Biomechanics:Sequential summation of forces. Retrieved from http://www.pestudiesrevisionseminars.com.au/pdf/Stage_2_Biomechanics_2nd_ed_sample_package.pdf

Punkh, N. (2013). How to improve my height? Does it help in badminton?. Retrieved from http://www.how-to-play-badminton.com/how-to-improve-my-height-does-it-help-in-badminton.html

Sakurai, S., & Ohtsuki, T. (2000). Muscle activity and accuracy of performance of the smash stroke in badminton with reference to skill and practice. Journal of Sports Sciences, 18(11), 901-914.