Saturday, October 26, 2013

Saturday Studies - 10/26/13

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Core Muscle Activation and Activity Throughout the Different Phases of the Golf Swing: A Literature Review

This great study dove deep into the research pertaining to muscle activation during the golf swing.  It looked at different phases of the swing - back swing, down swing, contact, and follow through - and the muscles active and dominant during those phases. 

They found a couple of things, some obvious, some other pretty interesting

1. Sequence Holds True - All high level golfers use the same sequence - Hips, torso, shoulder, arms, club.  Lesser golfers don't take advantage of this sequence to the degree high level golfers do.
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2. Glutes and Core - Overall key to golf power and club velocity is strong glutes and a strong core.  The researchers noted that improving strength in these areas can improve club distance by 6% or more.  That's pretty dang significant when we're talking about 150-250+ yards with many clubs.

3. Importance of Rotator Cuff and Scapular control and synchronization - I found this pretty interesting and probably not something a lot of golfers think about, the importance of a strong and stable shoulder.  Here's a quote from the study

       "while golf does not require an extremely demanding arm action, it does, however, entail highly synchronized rotator cuff muscle activity so as to protect the shoulder complex, especially during the downswing. These findings agree with research that also considered the activity of the scapular muscles in the upper back region (levator scapulae, rhomboid, trapezius, serratus anterior) throughout the golf swing. These data indicate that the upper, middle, and lower trapezius muscles work collectively, assisting in the retraction of the scapula throughout different sections of the swing"

4.  Professionals Don't Use DIFFERENT Muscle Activations - This should be encouraging for most golfers, to know that they guys you're watching on TV are using the same muscle activations as you - they just use them better.  They are stronger, more mobile, more efficient, and more consistent with these activation patterns.  This just reinforces the need for golfers to get into a strength and conditioning program that focuses on building the ranges of motions need, and then adding strength and stability on those patterns.

Check out our Prezi on Golf Performance HERE

2. Stretch and Activation of the Human Biarticular Hamstrings Across a Range of Running Speeds

The hamstring complex is an extremely important group for athletic performance.  The hamstrings help to extend the hip, and this hip extension is key to running speed and jumping height.  The hamstrings are made up of 3 muscles - biceps femoris, semimembranosus, semitendinosus.  The study looked into the amount of activation and different stretch lengths of each hamstring muscle during slow and fast running. 

The researchers found the stretch of each hamstring muscle was very similar.  This means that all 3 muscles were put through similar muscle-tendon unit stretch during all the speeds.

The researchers also noted that muscle tendon lengthening velocities were fairly similar, but as the running velocities increased especially at 6.9m/s, the biceps femoris lengthened at a velocity higher than the others.  This points to why the bicep femoris may be the most commonly injured hamstring muscle.  On the other hand, the muscle tendon unit shortening velocities were also very similar with the semitendinosus having the largest peak shortening velocity.

When looking at the EMG of the hamstring during the sprint cycle, 2 periods peaked on the activation scale

     - First was the portion of the stride from foot-strike to terminal stance
     - Second was from terminal swing to foot-strike

Both of these instances make sense as this is the hip extension portion of the gait and the hamstrings act as a key hip extensor.  Another interesting point was the medial hamstrings (semimembranosus and semitendinosus) were activated longer and more pronounced than the lateral hamstrings (biceps femoris).  What was also very important was to note that as speed increased, so did hamstring activation levels.  It's been said for a long time, the hamstring group is the most important muscle group for building speed.

This study is very interesting and may help shed some light on how to train the posterior chain specifically for sprinting.  We know certain exercises can stress the medial and lateral hamstrings more heavily and we can approach our training to mirror the same tendencies seen during actual sprinting. 

For example supine leg curls (stability ball, towel, valslide) and glute/ham raises target the lateral hamstrings more, and possibly training these more eccentrically may combat the risk of injury and better simulate the action during running.  Kettlebell swings and RDL's target the medial hamstrings more and making sure we perform dynamic efforts in both of these lifts may help simulate how they perform on the track.  These are ideas, nothing concrete, just thinking aloud.  Also "primetime's" or straight-leg bounds could simulate the actions of the posterior chain without the pounding and CNS intensiveness of sprinting.

Go Get 'Em!

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