How does relaxing your muscles strengthen the power of your smash [physiologically]? I'm looking for a biological explanation and not an anecdotal evidence. Thanks in advance!
To get power into a shot or anything, u need to generate force. This force will come from the contraction of muscles. If the muscles are already contracted, how can they contract any more to generate more force. Whereas if they are relaxed and then contract, there is so much more work to do there and more scope to generate power. The idea here is correct, the terms used may not be 100% correct but i hope you understand wot i mean
Read about fast twitch muscles here: http://sportsmedicine.about.com/od/anatomyandphysiology/a/MuscleFiberType.htm "Explosive" movements use fast twitch muscles. The correct way to perform a smash is through explosive movements instead of pure strength. You should also read up on a section in the Vertical Jump Bible about fast twitch muscles. Do this as an example to illustrate why it's important to "relax" your muscles prior to performing a smash. Using one or two fingers, try to tap (one at a time or alternating) on a desk as fast as possible. You'll notice that as you try to get faster go faster, your forearm muscles will start contracting and the finger(s)'s movements will be slower. The minute you consciously tell yourself to relax the forearm muscles, you will notice that your fingers will move faster. When using the fingers to tap on the desk, you are activating your fast twitch muscles. Your skeletal muscles will actually hinder the movements of your fast-twitch muscles when they contract. By relaxing your body up until the moment you make contact with the bird, you will perform the explosive movement required to complete the smash without your skeletal muscles hindering the quick burst of energy. If anyone is interested in reading the Vertical Jump Bible to learn more about explosive training, please pm me your email, I will send you a copy for personal use only. There are many things we, as badminton players, can borrow from other sports. Parts of my training comes MMA, sprinting, soccer, vertical jump, and power lifting. PS. It is commonly accepted that the skeletal muscle's hindrance to your fast twitch muscles is a self protection mechanism. It is to prevent your fast twitch muscles from tearing off your ligaments etc.
Both excellent answers! May I add that for the whipping action to be effective in power shots, we need relaxed muscles and joints until the point of strike when forces have to be quickly generated by fast twitch fibres. Much like the snap of the whip.
Rather than all that stuff about the muscle unit, I do have another explanation. Let's say you hold the racquet with a tight grip and tense arm - especially when doing a smash. That means most of the muscles in the arm will be tensed. Let's now view the elbow joint in isolation: there is the biceps and the triceps. Their movement on the elbow is antagonistic to each other. If both are contracted equally, then the elbow joint doesn't move. If both are relaxed equally, the elbow joint still doesn't move. How about if we want to extend at the elbow joint, e.g. smash. That's a triceps contraction. If you are tense, or trying to use a lot of strength, the biceps would also be in a state of contraction and this would slow the extension of the elbow joint. If you can relax your biceps and have the same contraction, the speed of extension of the elbow joint would be much faster. Apply the same principle to the extensor and flexor digitorums in the forearm (these control the fingers). If you can control the state of relaxation of the opposing muscle - i.e. have it very relaxed - then the movement will be much faster. If you have both sets of opposing muscles in tension, you 1) slow the movement, 2) waste energy.
^^ Sequential muscle recruitment. The right muscles have to be relaxed and contracted at the right time in sequence to get the whipping effect. This whipping effect can't be emphasized enough as it is critical for all power shots in badminton.
