Groin Kick Syndrome

Groin Kick Syndrome

Dr. GJohn Mullen Blog, Competition, Dryland, Training Leave a Comment

“Fast feet”
“Get those feet moving”
“Bubble, Bubbles! My grandma could kick faster…and she’s been dead for 20 years!”
These expletives are thrown around the pool deck more than a kickboard slicing through the air like a Frisbee. In swimming fast feet are associated with fast swimming, however, fast hands don’t always correlate with fast swimming.
In regards to the upper body, distance per stroke and obtaining a long reach desired for stroke efficiency and energy conservation, but distance per kick and kicking efficiency are never (I don’t say often) discussed upon the pool deck. Think about it, if a swimmer can go as fast with fewer kicks, won’t they save energy and become more efficient?
Kicking is essential for optimal swimming. More and more elite teams are putting higher volumes of kicking into their programs. This volume directly improves many swimmers, but every coach knows swimmers whom never become adequate kickers despite countless yards and frustrations while being lapped in practice by an all-star 12-year old girl with a huge magnum, bobblehead.
I have worked with many swimmers who die at the end of their races. Fatigue is a multi-variable resultant seen at the end of a race. During every optimal movement screen I have the athlete perform specific movements looking for overactive, weak, long, and short muscles, but first of all, I ask the swimmer where they feel they fatigue with the arms or upper body being the most common response. In my opinion, simply asking swimmers or knowing where the athlete fatigues are essential for improvement as are only as strong as our weakest link.

Poor Conditioning?
Arm fatigue is experienced by many swimmers at the end of all their races and most of the swimming society purely chalks it up to poor conditioning. Poor conditioning may be the cause, but from my experience, simply using more yards or improving arm strength does not improve the situation. Poor conditioning isn’t always the answer! The more you put in doesn’t necessarily make it correct! The person with their turn signal on for 15 miles isn’t the most likely person to turn! The swimming community needs to make theories and hypotheses on how to improve a subject/problem once a strong background is obtained on the subject.

Is the athlete to Blame? 
Our sport constantly puts blame on the swimmers chalking poor conditioning or inefficient feel without attempting to find a solution to these problems. In my opinion, everything has a solution. The solution isn’t the same for everyone and sometimes the rationale behind the answer is poor or inadequate, but an answer for everything is out there, but if you don’t try you’ll never find it!

Leg Lock
Now it is time to connect the dots between upper extremity fatigue and distance per kick. Too many coaches have tunnel vision, simply providing viewing a problem has a simple one variable algebraic equation. In my opinion, upper extremity fatigue in elite swimmers starts in two places: inefficient breathing/jaw relaxation and/or poor kicking efficiency, preventing axial hip rotation and more stress put on the upper body. These indirect hypotheses require deductive reasoning and an understanding of the connective chain, let’s discuss how fast feet contribute to Fred Flinstone arms.

LLNFG is a horrible acronym to remember the Groin Kick Syndrome, but focus on the process rather than the name!

Leg Spin–>Leg Lock–>No Ro(toation)–>Fred Flintstone arms–>Groin Kick Syndrome (GKS)

  1. Leg Spin: Many swimmers are conditioned at the end of a race to increase their kicking speed. This causes swimmers to spin their legs, not adequately allowing a fluid efficient kick. Kicking forward propulsion is controlled by hip flexion and knee extension, similarly to kicking a soccer ball (just with not as much hip extension). This motion allows whipping and energy transfer to maximize propulsion. Unfortunately, when the legs spin the fluid soccer like kick is replaced with an inefficient movement. A lack of efficient decreases the kicking economy while using more and more energy. The more energy consumed/used leads to a leg lock.
  2. Leg Lock: The legs contain the largest volume of skeletal muscle in the body. These monstrous areas consume a lot of oxygen and are unfortunately located far away from the lungs. This consumption leads to massive fatigue (decreased pH, decreased PCr, increased CO2, etc.) increases and fatigue in the legs locking them up and causing No Ro(toation).
  3. No Ro: The strongest muscle in kicking is the rectus femoris (one of the quadriceps). This muscle crosses both the hip and knee joint allowing both motions for a fluid kick, hip flexion, and knee extension. Once locked the rectus femoris prevents hip mobility. Without proper hip mobility, the swimmer is not able to rotate their body properly, to use a hybrid or hip-driven stroke. This result is disastrous and causes the athlete to swim like a brick in the water with high frontal drag. 
  4. Fred Flinstone arms: Once the legs are locked the body plows through the water relying on the arms for all forward propulsion. At this time, the arms start to spin, causing fatigue/increased fatigue metabolites/decreased “feel” and Fred Flinstone arms. As the arms fill with fatiguing metabolites and the body enters groin kick syndrome.
  5. GKS: Every post-pubescent swimmer has experienced GKS. It runs rampant in over-confident or naïve swimmers trying distances longer than their capacity. Once the arms and legs tighten and the bodies engulfs fatiguing metabolites and the body becomes acidic with massive fatigue. This poisonous shift is harmful to success and halts many swimmers at the flags as they try to get to just get their damn hand on the wall.


Like I said, every post-pubescent swimmer has experienced GKS and will continue to do so, but if you continually experience GKS and achieve Fred Flinstone arms at the end of the race, maybe adding 1,500 pull at the end of every workout isn’t the best answer. Instead look at the beginning of the continuum…leg spin. The next installment of GKS will look at methods to improve distance per kick (DPK) and kicking efficiency.

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