Biomechanics: Questions and Answers by Dr. Scott Riewald (2002)


The following comments are answers to questions from the audience.


Question – There are a lot of things that go into stroke mechanics. One is having a kinesthetic awareness – what it feels like to actually do that movement. If you can teach swimmers what it feels like to do a movement, that does a lot more than standing on the deck saying, no that’s wrong. Go through a stroke or a pull cycle, or have them pull on a railing to get the general idea for what it should feel like in the water. You want to give them the feel of the movement. Maybe do this on a vasa trainer. That is going to help them perform better in the water.


Question regarding decelerating or creating negative forces. That is .1 to .15 seconds depending on how the hand is angled. It could be a little bit shorter or a little bit longer than that, but that is a generally good rule of thumb. If there is a decelerating phase in your stroke, a tenth of a second to 1.15 seconds, it could last longer than that and you are actually slowing yourself down. If I were teaching new swimmers how to catch the water in freestyle, I would probably start everyone thinking about distance-per stroke type of freestyle. This includes getting that high elbow catch, getting into a position where you are feeling pressure on your forearm and your hand, and just pushing water back towards your feet.  A good drill that you can use to incorporate that feel on the forearm is swimming like this (picture). I know a lot of coaches do that drill already, but that gives an athlete a good kinesthetic awareness. “My forearm actually can do something when I pull it is not just there going along for the ride.” Those would be the things that I would want to focus on, getting some reach. The first action is to pull with a straight arm and pushing water towards the bottom of the pool. Get that elbow up high. I hate to continue using Ian Thorpe as an example, but you watch him. Watch Grant Hackett and Kiernan Perklins, their elbow stays in the same position from this point to this point. This is not something that just comes naturally; building up strength in the forearms is something that needs to be done as well.


I will comment on the distance per stroke.  I went to a summer meet in Pratville, Alabama this summer and it had a lot of lower level young kids. I asked the age group coach – why do age group coaches even carry stopwatches? He said “all that matters at that real young age is learning how to set up strokes and increase distance per stroke”. So, for whatever that is worth, that is what he was referring to.  So here we got some video of Ian Thorpe swimming freestyle. We got some underwater footage to point out some of the things that I mentioned before. Watch Ian Thorpe’s underwater arm position and how quickly he gets into that high elbow position. Look at his pulling mechanics – again, I said I wanted to steer away from looking at the best and then trying to mimic what they do, but he follows a lot of the things that we are suggesting in terms of the research that is coming out.  There is very little sculling in this pool.  There is very little sculling in Grant Hackett’s pool.  Just grab the water, push it back towards the feet, and get into the next stroke.  Any kind of deviation from side to side that you are seeing in his stroke technique is coming from body roll. If you took the body roll out it would be pretty flat in terms of his hand moving from the front of his body back towards his feet.


Question – what is his angle of attack? He kind of leans into his arm a little bit. Watch Ian Thorpe and as he extends his arm he kind of leans on his shoulder and drops his elbow just a little bit before he gets into the catch.  It seems to work effectively for him.  Now I don’t necessarily recommend this for every athlete because it puts the shoulder in a position where you really externally or internally rotate it and that is a typical position for impinging his supraspinatus tendon. I don’t necessarily recommend that for every swimmer.  If you want to play around with it and see how it works that is one thing. I am sure that there are going to be athletes who can do it and come away from it injury free, but my hesitation would be that you are putting an athlete in a position where maybe an injury is more likely to happen.  Yes, they do have an asymmetric stroke pattern. There is a tendency for that in almost every freestyler – or every swimmer – that they are not the same on the right and the left.  If we had the video from above, looking down at Ian Thorpe you can see that he’s got a fair amount of wiggle in his stroke. By all means he doesn’t have your perfect stroke from a physics sense of the word, but he does a lot of things right. There are asymmetries, but as a coach, I don’t think you are ever going to be able to get away from that with your athletes.  The ideal situation would be to have them be symmetric right and left side, but I don’t think we are going to see it.


Question – Coach Gosef pointed out that if you are only breathing to one side it might require a different force pattern with one arm versus the other arm. I think that is true.  Everytime you breathe there is a balance that needs to occur with the opposing arm to keep your body from going out of wack.  Now a lot of times you talk about core stability and using the core of your body to set up that balance in the water. But to some degree, you are using your catching arm and you are using your legs as well to maintain that sense of balance. Really effective swimmers are using their core more than ineffective swimmers who are relying almost entirely on their arms or their legs to achieve that balance. That is a good point.


Question –how far back and how do you want to finish your stroke.  From a physics perspective, and we are not talking about fluid mechanics here, you don’t want to lock your arms out and finish with an arm extended.  Anytime you can make things more circular as opposed to up or straight stop, start and stop, front and back; you are going to be more energetically efficient. So you want to round things off at the back of the stroke and pull out with your elbow before you get to that full extension point.  You also get to a point where you start to extend your elbow. Once you start to do that, you are starting to chop down the pulling surface that you have.  You are still able to pull with your hand, but the point surface of your forearm as you are extending your elbow is gradually going away so you are losing potentially half of your pulling surface. So you don’t really want to go to that full extension, pull out with your elbow and stay with your hand at or past your hip.


What’s that? They are not really coming to full extension. They are kind of rounding out and may be keeping their elbow straighter, but they are sweeping around as opposed to kind of coming straight over.  No one has the shoulder flexibility to finish here and come straight over so it is a rounding off to the outside as opposed to lifting out with your elbow.


What’s that?  I can’t really answer that.  I am not really seeing someone or visualizing a straight-arm freestyle. I haven’t actually looked at a straight arm freestyle with that question in mind.


Question – the question concerns training the musculature of your upper body and arms – what can be done differently to get athletes to swim with a higher elbow catch as opposed to a starting arm catch or an inefficient catch. The answer is yes. I think that anything that you can do that is sport specific or that is specific to that movement is going to help.  So, I know that I have mentioned the Vasa trainer before and I am not here as a public spokesman for Vasa, but I would recommend its use. You can go through the motions, you can change the resistance that an athlete is experiencing and you can strengthen the musculature in the arms and the shoulders for that specific motion. Some other muscle groups that you want to think about strengthen are the muscles that stabilize your scapula. Your shoulder doesn’t operate independently. Your elbow doesn’t operate independently of the shoulder and your shoulder doesn’t operate independently of your shoulder blades. They are all linked together. They are only as strong as your weakest link and for a lot of people, that weak link is the shoulder blade stabilizing muscles. There is a series of exercises that you can do and they are posted on the USA Swimming website. There is an article that just went up on USA Swimming about preventing shoulder injury and strengthening those muscles. So those would be some of the muscles you can choose as well as core musculature. This will help with your balance in the water.


Question – the question is what are my thoughts on hand paddles. How should you use them and are there better ones.  I am going to say that my opinion on hand paddles may differ from a lot of yours.  I look at hand paddles as a strength training tool just like you might look at a bench press machine in a weight room. Hand paddles are probably one of the best sports specific ways of increasing strength. But I know they are not used that way by a lot of coaches and athletes. Say I did a 2000 pull with paddles and had the athlete go on their way.  You would never go into the weight room and give 2000 reps of lat back pull downs and say come see me when you are done. Their muscles would be toast. I see paddles and fins in kind of the same way – paddles more so than fins actually.  What I would like to recommend in terms of paddle size is they should be slightly bigger than the hand.  There is no need to get these big things that are 4 x as big as your hand. Most athletes don’t have the strength to use those paddles correctly. Something that is a little bit bigger than the hand is all you really need and then encourage your athletes not to slack off when they are using them. As soon as you put a bigger pulling surface on an athletes hand, they will quickly realize they can swim the same speeds that they were without the paddles with much less effort. So expect a high level of performance when you put the paddles on but keep in mind that you are using this as a strength-training tool. Design your sets like you would design a set in the weight room. That is how I approach paddles.


Question – what is the importance of body rotation? You look at other sports. Look at Tiger Wood swinging a golf club and he generates all the momentum and all the power for his swing from his torso and from his legs.  You don’t really have that solid base of support in swimming.  In some sense, you are never going to have that rigid support that you do when your feet are planted on the ground. The kick, to some extent, serves as a stabilizer and provides balance. This can be used as a platform that you can use to drive some rotation. I know that it is preached almost all the time – drive the rotation from your hips.  Some athletes are able to do that and you can watch them on video and see that.  For most athletes, the best they are able to get is that synchronicity between the shoulders and the hips, but the hips aren’t really leading.  I think that is what you can shoot for.  If you get into a situation where your upper body is really out in front of your hips it is kind of a loss of energy.  You are dissipating energy as your legs go along for the ride and they are not really contributing. The core of your body has nothing to do with the propulsion that you are generating.


Question – You might emphasize different things in the weight room in different parts of your season, maybe at the beginning of your season you are looking to develop power or to develop some muscular endurance.  I’ll have them do some longer sets, say 30 repetitions of an exercise to develop that muscular endurance with several sets of it. I don’t see anything wrong with doing 100s and 200s in the pool to kind of elicit those same sorts of things. As you get closer to your competition you are probably specializing on power development and explosiveness in the weight room. You are doing sets maybe of 3-4, 5-6 reps at a higher intensity to elicit that power. You can mimic that in the water as well by doing 50s of high intensity work.  Or you can do 25’s of high intensity work. I would say you are defeating the purpose to have them go and just do an 800 pull in that phase of their workout. Use some creativity to design some sets and remember you should mimic what you are doing, emphasizing the weight room as well.


Question – Again, I hit on it before, but the shoulder doesn’t operate independently of the upper back and the muscles that control the scapula.  When you raise your arm and get in this position, there is a certain amount of elevation that comes from the shoulder. There is a certain amount that comes from the shoulder blade rotating.  If you are weak in your shoulder musculature or your shoulder blade musculature, you are putting added responsibility on the shoulder and you are stressing those muscles a little bit more. So developing a good muscular strength and muscular balance throughout the upper back and throughout the muscles that stabilize the shoulder blade is going to put you in a position where you are much better able to head off or treat any kind of shoulder problems.


Question – I don’t know what he is doing for strength conditioning in terms of strength throughout his body, but I got to believe he is either genetically predisposed to not getting it. I have seen people with the most horrible strokes that turn out thousands and thousands of repetitions and never once have an inkling of shoulder problems. Then someone that you would consider having great stroke technique – boom – a major shoulder problem pops. There is a lot in terms of genetics that goes into it, there is a lot that we don’t know, but in terms of his overall muscular strength and balance, that is helping.


Question – about flexibility. That obviously plays into it to some degree as well, but it is not a determining factor.  There are a lot of things that go into a shoulder injury. What causes it and how you can treat it – we are in the process of developing some educational material including videos and we have a series of exercises to try to strengthen the muscles that are appropriate to stay away from. That is really all I can recommend. It is going to happen to some swimmers.  It is not going to happen to others despite your best efforts to keep it away.  I don’t know if I can add anything more than what I have already said.


Question – how should a young athlete who is learning to swim have their hands positioned, where should they be in terms of the midline of the body? – You definitely don’t want it coming across the centerline. I think that you are most powerful in shoulder width to the middle of the body part. You should avoid crossing over the midline of the body.  Another thing to think about is that the shorter the distance between the shoulder and the hand, the more force you are able to apply to the hand.  It is just the law of lever arms – the farther away your hand is, the smaller the force is that you are able to deliver to the water, Obviously, the closer you get you are going to start to run into interference effects. So probably about a foot and a half away from the body at an elite level adult swimmer is where you want to be. This is not for shorter kids; their arms are shorter so you have to adjust that, as you will. That is what is going to give you the most effective pulling mechanics.


Question – Coach Marsh asked how does some of this stuff apply to the other strokes?  Well, butterfly is very similar to freestyle; you are just doing it with two arms at once. A lot of the same things apply that we talked about in freestyle to the butterfly stroke. Obviously, this is different for breaststroke. Breaststroke is the one stroke that the majority of your propulsion comes from lift forces as opposed to propulsive drag forces.  Interesting though, how you have seen the breaststroke develop over the years.  Getting out and getting into that high elbow posture when you turn the corner, you get ready for the in-sweep. If you were to split a swimmer down the middle and you observe the different catch phases for freestyle, butterfly and, breaststroke, it would be very difficult for a lot of people to tell the difference between the three.  That same kind of high elbow catching position is very similar in all three of the strokes. Obviously, what you do from that position differs depending on the stroke, but that posture is common throughout all three strokes.


Question – Coach Marsh asked if, based on this research, do I advocate a more straight pull back in breaststroke as opposed to a sweeping in-sweep.  I don’t necessarily know that I would advocate that.  You may be able to generate more propulsion, as much as you might in the butterfly pull, but then you deal with what you do with your hands and your arms once you get to that position.  You have to recover them back through the water and that kind of recovery process is going against the direction that you are moving. This obviously generates a lot more drag and I think it would outweigh the benefits that you might get from pulling straight back in a breaststroke pull. Maybe that is something you can play around with as coaches and see if there is a happy medium pointing back slightly and then in-sweeping. It is something that is worth tinkering with.


Question – Is there one type of backstroke that tends to be better for younger athletes in particular. Some differences that you see in backstroke occur predominantly in the depth of the stroke and whether you have a bent arm or a straight arm in your pull.  A lot of this has to do with flexibility and what you are able to do.  A person that is really flexible in the shoulders is able to get a deeper catch, bend that elbow a little bit more and start that pull towards their feet a little bit earlier in the stroke cycle.  If you are not as flexible in the shoulders, the tendency is to pull with a wider stroke and a shallower stroke.  My recommendations are to try and go for the former rather than the latter and get that deeper catch. Keep the elbow at a higher position but with the hand and forearm oriented towards your feet so that you can generate as much propulsive force as you can. The rotation aspect – the hip rotation and body rotation does play a greater contribution in that stroke than in the flat backstroke where he might be a little bit wider.  I think this places a little bit more stress on the shoulders as well, pulling wide, you start dealing with the physics of the motion. If you are pushing water to the side you are going to start fishtailing. The deeper catch, bent arm backstroke would be the way that I would teach it if you had the flexibility and the athlete to do it.


Question – how do you want to have your hands? The ideal situation is to be generating as much propulsive force with your forearm and hands, how do you want your arms to be once you pass this midway point in your backstroke? Well obviously – you have two things battling each other here.  You have the issue of generating that force and making that force go in the direction it is actually going to help propel you down the pool.  You are generating a lot of force and you are pushing it towards the bottom. You probably don’t want to be in that type of situation so you got to weigh those two things together.  As long as you can keep your forearm and your hand operating in the same plane and pushing water towards your feet you are okay. When you reach the mid-point or slightly past that in your stroke, this amount of area is decreasing and you end up pulling predominantly with your hand. If you allow that to happen, recognizing that your hand is becoming the predominant force generating body and keeping that force directed towards your feet rather than being concerned with trying to keep this hand arm alignment, you will possibly end up pushing water toward the bottom of the pool.  In-sweep again is more lift dominated. Adjust the angle of attack so that you are generating as much lift force and propulsive force forward as you can.


Question –at what point in an in-sweep of a breaststroke should the palms be rotated towards each other?  I think that they should be from the start of the pull and as you come through they rotate a little bit more towards each other.




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