i am trying to pronate forearm while hitting forehand shots. I have a doubt regarding the angles. for maximum power, how much angle at elbow and between racquet & forearm 1. during presparation 2. at the point of contact with shuttle? thanks.
1. In preparation, the elbow angle should be acute (less than 90 degrees); say, about 45 degrees). This provides better balance, rather than having a larger angle where the weight of your arm behind you can throw off your movement slightly. There should be no angle (0 degrees, or very nearly) between racket and forearm. The wrist should be in an approximately neutral position, and relaxed. 2. At the point of contact, the elbow angle should be obtuse (more than 90 degrees, but less than 180 degrees). Say, about 135 degrees. This allows you to reach high yet hit with a bent arm (gives more power). The angle between racket and forearm should be slightly less than 90 degrees; say, about 75 degrees.
Hitting with a bent arm will not give you maximum power. For almost all shots, clears, smashes and drops, the arm must be straight at point of impact, for power and control. A bent arm, whilst necessary at the initial stages, will lose power and control when you make contact with the shuttle. As an unwanted bonus you may even get tennis elbow. Bent arms at point of contact look crude. Straight arms look more elegant because it is more efficient.
Hmmm. It's very difficult to distinguish between "at impact" and "fractionally before impact". The angle at impact will obviously be straighter than fractionally before impact, where the arm must be somewhat bent. It's hard to be sure how close to straight the arm will go at its maximum extension. Nevertheless, there is an inherent risk in allowing a completely straight arm: when the joints are at their extremes of motion, they are much more susceptible to injury. The advice from Badminton England is to hit at "full relaxed reach". I think this is a very good phrase that avoids the perils of over-analysing the precise transitions of angle (players are unlikely to know exactly what their arm angle is at impact; if you tell them to hit with a straight arm at impact, they will inevitably use too straight an arm too early).
I believe there was a scientific study some time ago that showed that to get most power from pronation, the angle at the elbow should be around 135. I'm sure there was a link to it and a thread about it in BC somewhere. maybe 3-4 years ago edit: or maybe 147 degrees www.badmintonforum.com/vb/showthread.php?t=2412
It looks like the 147 degree comment was in reference to the angle between the forearm & the shaft of the racket rather than the amount of bend (or straightness) of the arm at the elbow. I would have expected the angle at the elbow to be a somewhat greater than 135 degrees yet still less than 180 degrees. Inspection of elite players show that some are closer to straight (nearly 180 degrees) than others. I like that phrase "full relaxed reach". You don't want to hyper-extend that arm trying to get it absolutely straight. Biomechanic analysis suggests that the arm generates somewhat more power in a throwing motion and for swimming strokes when the arm is slightly bent rather than completely straight. It would seem that the slight bend at the elbow allows for a more efficient use of the shoulder and various muscles of the arm & torso. Some biomechanic experts also claim the the slight bend minimizes injuries by using the shoulder & arm more efficiently. Currently there is a controversy brewing in the cricket world 'cuz some bowlers have developed very effective pitches using a slight bend in the arm rather than the conventional straight arm. .
Badminton.tv , in their video "the racket arm", use Steve Butler's excellent teaching method: In preparation, the elbow should make a sharp V shape (acute). As you hit the shuttle, the elbow should make a wider L shape (obtuse). You have to explain that the L shape is obtuse (for those who interpret things entirely literally), but it's a good teaching aid nevertheless.
Okay, time to pull out some physics to put an end to this. First of all, strokes consist of rotational movements rather than translational movements. Just imagine how ineffective it would be to "push" a smash over the net (actually, many beginners to try to do this, that's why they have so much trouble generating power). Suppose you have a two segment system with a simple hinge joint between segments. Let's say that segment 1 is rotating about its axis with the joint angle fixed at angle theta. There is a limited range of motion available for segment 1, and it must accelerate and decelerate within that range. Consider the case of theta = 180 degrees. In such a case, the moment of inertia I is very low, and the maximum rotation speed will be reached very quickly. However, the maximum radius of rotation is very small (almost 0), so there isn't a lot of linear velocity generated with this joint angle. The next case would be 90 degrees. Moment of inertia is much higher -> this means that you can spend much more power to accelerate the system up to maximum rotation speed. The radius of rotation is given by: r=L*sin(theta), where L is the second segment length. As you can see, at 90 degrees gives the maximum value for this function. Maximum linear velocity is given by v=rw, where v is linear velocity, and w is angular velocity. How about for an angle of less than 90 degrees? In the perspective of a two-joint analysis, it provides no benefits. Real System Things get a lot more complicated as you add more joints/segments to the system. There are many more degrees of freedom. Now you're optimizing segment n's linear velocity with respect to (n-1) angles. To add even more complexity, many joints in the human body are much more complicated than simple hinge joints. There are two rotations to consider at the shoulder: internal rotation of the humerus and the downward rotation of the arm. The wrist can deviate laterally as well as rotate relative to the elbow. Let's consider the wrist, which is the last major joint of our model. It'll be at 90 degrees when the pronators are most active, the angle will increase at some point to help optimize the moment arm for another joint(s) and then go back to 90 degrees for when the supinators are most active (deceleration phase). Now, pronators are very strong (in fact, probably their strongest) in the range where you increase the angle, so you're not going to go all the way to 180 degrees to help power transfer in a more proximal joint. So how much? It really depends on that individual's relative joint strengths and limb lengths, etc. But generally it'll go from 90 degrees -> ~135 degrees -> 90 degrees. So, the joint angles used will depend on 1. relative joint strengths -> muscle strength, reactive strength, tendon-muscle ratio, muscle insertions 2. limb lengths 3. amount of time/space available for the stroke 4. stroke type (e.g. wrist shot vs full swing)
If you uncock your wrist at the right time, a straight arm at point of impact will generate the most power and also the best control. One stroke to try this is the straight backhand smash or drop, the former a Taufik specialty. If you uncock your wrist too early the expected added power will be expended before the shuttle is hit. If you oncock it too late, it will not have time to build up maximum effect. There are players with arms that are bent and not straight, either from injuries or other causes. It is harder for such players to get maximum power because they simply cannot play with a staright arm even if they want to. There are some simple stretches and dumbell exercises that you can do to straighten your arm slightly. Watch all the top players and it is always a straight arm, although sometimes, rarely though, they are caught with a slightly bent arm which often produce a poor shot.
About a week ago I was watching a brother and sister, aged about 9 and 10, being trained by a coach. I was amazed by the power, grace and speed of the girl, especially for a 9 year old. I asked the coach to videotape them but was turned down. Their one hour practice consisted of clears, jump smashes from the baseline and lifts. Although the elder brother looked stronger the younger girl just looked more fluid, more powerful, almost ballet-like movement. Her outstanding quality that stood out was how straight her arm was, for clears, smashes, and the high serves, and the way she transferred power from her body movement. There were other players and coaches around and they, like me, just watched in amazement at such talent at such a tender age. Incidentally the net towers over their head. But it was the arm, the arm, and a straight one at that, that really stood out.
That's funny, I was going to say that if you study any of the elite international players, you will see that they DON'T have a straight arm when playing overheads. Are we looking at the same players? For example, Taufik most certainly does NOT have a straight arm when playing his backhands (nor does anyone else who know's what they're doing). One thing that can lead to confusion is that racquet swings are pretty fast these days. The arm may LOOK straight, but if the player is any good, it won't be straight. They whole straight arm thing is a throwback to the 60s and earlier when racquet technology was quite different to what we have now. A former coach of mine was a player of that era (won a few big tournaments, semi finalist at the All Englands, etc) and she was always quite insistant on reaching as high as possible for the shuttle. However, despite being a little "old school" in terms of technique, she was a fantastic coach with regards to mental strength and tactics. Wayne Young
One thing anyone can try on their own is to hold the racquet with various wrist angles, and apply quick pushes on stringbeds. Observe how effectively you can resist these pushes. At 90 degrees, and also 135 degrees, it is a very fast response. At 180 degrees, the response is quite slow. This means that when hitting a hard shot, the wrist can absorb a lot of your kinetic energy at contact.
All power shots require a straight arm and that includes all overhead shots like smashes and clears, power underhand shots, drives and fast drops for maximum power and control and, yes, they also look extremely elegant. Just watch a powerful smash with a bent arm and you will be convinced you don't want want to smash that way. A bent arm smash looks ugly and is used by players with a very high percentage of them having to use elbow braces. Sometimes clears are seen to be played with a bent arm, probably due to the fast pace of the shot that went over the head too fast to reply with a straight arm. This doesn't mean playing a clear with a bent arm is the correct way. Try to watch a clear that hits the shuttle with the upper body moving foreward, after bending backwards, with a straight arm at point of impact. It is effortlessly powerful and precise and it looks better. I think the serve, footwork, wrist cocking and uncocking, and the straight arm should be the fundamentals that every newcomer to badminton should learn. This will make the game of badminton a more beautiful game with reduced tennis elbow injuries.
Taneepak, it sounds like your badminton is a little different to what everyone else plays or watches. We are talking about the game with the feather birdie thing, aren't we? Wayne Young
This is becoming an interesting thread. I still believe fundamentals are fundamentals (like taking the birdie at the highest point or early in time is best) and do not change. If they change then they should not be considered fundamentals. I have been around longer than most of you and I can say that today's players play more with a straight arm than players in the past. In the old days the round-the-head smash was unheard of until Rudy Hartono introduced this stroke. This smash is perhaps one of the most powerful shots in badminton. The straighter the arm the more powerful and the more accurate the round-the-head smash. I am frankly surprised that use of a straight arm is not well appreciated in this forum, as I consider it an important fundamental. There is a training video by Zhao Jinhua that touches on this bent and straight arm. Some of you may have seen this as they have been copied and pirated on this forum a thousand and one times.
Yes, it's interesting you mention Zhao Jinhua. I have no idea what he's saying as I don't speak Madarin, but it's clear as daylight in the slow motion video that his arm is bent when he smashes. Here's some pictures of some better than average players I found on this site after a very quick search. Bent arm... Bent arm... Bent arm... Bent arm (you can tell from the bicep)... Bent arm... Wayne Young
The photos are not conclusive. The arm should be straight immediately after contact with the shuttle, not before nor after. It is hard to judge this from the photos. Peter Gade's arm is not bent-it is a straight arm with pronation. Zhao Jinhua's arm as shown is not at the point of the split second after contact with the shuttle but before contact. His arm is still very slightly bent just before contact, as it should be. BCL and LD show strokes after a smash, not the split second after contact. Wijaya's shot looks more like a smash return instead of a smash. How about showing some photos of powerful beginners or intermediate players who smash with a bent arm? These players tend to have a greater bend at their elbow, and their strokes look ugly. I would like opinions from others, including the better players.
You're right, Wijaya is returning a smash. My bad. You're welcome to find some pictures of top players smashing with straight arms. That's if you can find them, of course. Wayne Young
In the October 2006 edition of Power&Precision, the Badminton England coaching magazine, there is an article called "the beginner and the overhead clear". The article includes a technical analysis. Here's an extract: The article was written by Mike Woodward, England U15 age group coach and coaching consultant to BE.
The best way to find out is to go to a badminton hall with a few courts where you find some very players and some not so good players. You then compare the relative degree of arm straightness or bent of these two groups when they hit power shots. The difference will be obvious. You then concentrate on the very good players and although they will all play with a relatively straighter arm, you will find small degrees of arm straightness amongst them, in which case we are merely splitting hairs. The overall motion is a straight arm.
