The Fin Factor

I agree with Chris -- if high schoolers can't make a 1:45 kick interval, that is pretty pathetic and they need to work on it. They are probably too lazy to really work a kick set. Very common. Perhaps Q's theory is correct. I feel like my whole leg is recruited when I kick with fins, and it really helps to build leg strength. And personally, I'd rather do lactate work with fins rather than short rest intervals. Though I will occasionally do kick mountains for endurance work. I can kick fast with or without fins. I kick a lot with fins, but then it doesn't bother my ankles or knees in the slightest. I think both are valuable.

you probably have a fast kick that is slowed down by fins.... just my guess. i used fins today for the first time ever during a masters practice (800 LCM alt 50fr/50bk w/fins) and found that they didn't really change my kick much, but i swim primarily with a 2-beat.

Are you using the same fins as everyone else? Both 100s on 1:45 sans fins and 100s on 1:10 with fins would be close to impossible for me, but I do see a 10-15 second drop/50 with fins, so you only seeing a 4 second drop and being a fast kicker is kinda surprising. Here is my theory right now. You have very flexible ankles, and your propulsive force is from the foot, with very little benefit from the shin, and almost no knee bend. When you put fins on, you maintain the same style, and your propulsive force is limited by your ankle as the fulcrum instead of your knee. This analysis is based on almost no real evidence, and is very likely completely wrong. But it could be try. Try this experiment if you think I have a small hope of being right. Kick something you can time with fins like you normally do, a 50 or a 100. On the next one, try to whip your foot as much as possible from the knee, let the fin break the surface of the water and kick it all the way down to 30 degrees (the surface being 0 degrees) which is probably much deeper than you usually kick. Let your kick be quad driven. Compare times. Come back and make fun of my theory for being completely wrong.

One exercise I find that not only helps my core but my kicking is the Captain Chair Leg Lifts. Its that piece of equipment that you stand in, then hang, with your elbows & forearms on pad while gripping hand grips....you legs hang, then you bring your legs straight up as if you were sitting on the floor with your legs in front of you. Great for building up thigh and some of the hip muscles. For ankles, just calf raises should help some. I also try to work on the flexiblity of my ankles by sitting and rocking back on them (in socks on a pad/carpet).

Here is my theory right now. You have very flexible ankles, and your propulsive force is from the foot, with very little benefit from the shin, and almost no knee bend. When you put fins on, you maintain the same style, and your propulsive force is limited by your ankle as the fulcrum instead of your knee. This theory turns out to be true for me. I can kick a 50m under 40sec but I hate Fins so much that I'd basically skip a set if forced to use them. This piece of gear is irrelevant for me and above all, they hurt my ankles big time.

for me fins and paddles seem to increase the muscle load while decreasing the aerobic cost of swimming. someone with average v02 but very good strength(male/female, sprinter/distance?) should get more benefit from this shift. fins seem to forgive problems like bad body position so they should really help a strong swimmer with technique issues. also, fin kicking a lot does not seem to benefit naked kicking and vice-versa so you should be better at the one you do more of. :2cents:

Lots of great analysis here and it gives me much to think about. I do have incredibly weak ankles, so I do wonder if that might not be a factor. In fact, a podiatrist noted that in order to walk, my ankles are so weak that I've had to make up for it in my hip adductor/abductor area. Not only are my ankles weak, they are not very flexible. Another thing, a friend mentioned that when I kick, perhaps I use my core and hip abductors/adductors more than most. Could the problem be that I am overly dependent on core and hip adductor/abductor muscles for my kick and thus the fins don't make a big difference? My one rep max on the hip adductor machine is the entire stack, so I'm thinking the bizarre strength must come from overcompensation. Gee, I wish some of it would pan out on breaststroke, but no such luck. Great for cycling - maybe I should go back to that! The whole stack? Yikes! You might be onto something with the core & hip explanation. I have weak ankles too, though in my case it is BECAUSE of the flexibility. I would think fins would actually compensate for inflexible ankles. But you seem to have a strong kick anyway so they can't be that bad.

Chris, do you think cycling has given you a strong kick? On the whole, probably not. Maybe it helps with conditioning and endurance, but by far the thing that helps me the most is doing hard kick sets. I don't notice any correlation between the amt of cycling I do and my performance on kick sets. When I do cycling it is b/c I like it and to do something different, not really because I think it helps swimming a lot. (It probably helps some, but I don't know that the time couldn't have been better used in the water or in the weight room.)

The whole stack? Yikes! You might be onto something with the core & hip explanation. I have weak ankles too, though in my case it is BECAUSE of the flexibility. I would think fins would actually compensate for inflexible ankles. But you seem to have a strong kick anyway so they can't be that bad. Would really like to get the kick without fins even stronger. Chris, do you think cycling has given you a strong kick? I used to find that in the fall months following a summer of consistent cycling, my kick felt really strong. Kind of wierd that I do have inflexible ankles also. I was having some lower back issues a couple of years ago and at the urging of a good friend, went to see a guy in Huntsville that tests for muscular imbalances. He took about 2 hours to run a bunch of tests. On one ankle test, I tested very poor while on ankle inversion and exversion, I tested excellent. Maybe I should get him to test me again. Yeah, the hip adductor/hip abductor machine thing is kind of wild. It is the one and only thing I can beat the guys on in the weight room. Kind of wish I had taken up competitive cycling in my early twenties (rather than waiting until my mid-thirties to do it for triathlons), so I could have put this good strength to use. I kind of curious to see what a few months of some calf raises might do for my fins sets. I'm hopeful

I have weak ankles too, though in my case it is BECAUSE of the flexibility. I would think fins would actually compensate for inflexible ankles. But you seem to have a strong kick anyway so they can't be that bad. Some fins are stiffer than others too so it really depends. I think I have the TYR fins (green & black) and they were really stiff when I first got them. They still are compared to alot of fins but I'm used to them now. I don't do a ton of kicking with fins anyway.