8/09/2012

Eccentric Exercise. Bigger. Stronger. More Powerfuller. Resistant to Injury.


No, it's not a blog posting about weird exercises. It's about the ECCENTRIC or negative phase of resistance exercises.  This often under appreciated and ignored part of an exercise is important for:

1. Increasing strength 
2. Increasing muscle size
3. Giving you delayed onset muscle soreness
4. Producing maximal power, ie, in plyometric movements
5. Rehabilitating injuries like tendonitis and protecting muscles, connective tissues and joints from future injuries

Read on for some simple ideas and changes you can make to help improve your exercise program  ... whether you want to get bigger, stronger, more powerful, reduce the risk of injury , or speed recovery.

Often left unloved

Consider the Chest Press. Most people think this exercise is all about the pushing (or CONCENTRIC contraction). Have you ever just let the weights fall after the last push or pull?  If so, you've eliminated the ECCENTRIC part of the exercise. In a set of 12 repetitions, you're only doing 11 1/2. Skipping the ECCENTRIC movement also reduces the time that the muscles spend working.

In plyometric training, the often overlooked ECCENTRIC movement is important as a loading phase:  like a rubber band, the muscle stores elastic energy that is released in the CONCENTRIC movement.  For best results, perform the ECCENTRIC movement first with an immediate transition into the CONCENTRIC movement.  ECCENTRIC and CONCENTRIC movements for some common exercises are shown below. 

EXERCISECONCENTRIC
MOVEMENT
ECCENTRIC
MOVEMENT
Chest PressAway from body (push)Towards body
Row, Lat PulldownTowards body (pull)Away from body
Biceps CurlFlexing elbowExtending elbow
Triceps ExtensionExtending elbowFlexing elbow
Shoulder PressAway from body (push)Towards body
Lat RaiseRaiseLower
Lunge, SquatPushing body upLowering body
     
Wisely and slow

Your muscles work hard to resist against the weight - or gravity - in the ECCENTRIC phase. They slow the decent of the weight in a chest press or biceps curl, or of the body in a squat, or the return of the weight stack in a cable exercise.
  
Muscles forcibly lengthen during an ECCENTRIC contraction, and this is believed to cause more damage to muscle fibers and sensory organs than other contractions.  In fact, delayed onset muscle soreness is mainly attributed to the ECCENTRIC phase.   Why is it good to damage your muscle fibers?  Your body responds to this damage by repairing the damage and creating new fibers.  Your muscle's sensory organs adapt and respond better to future bouts of similar exercises.  So we get bigger and stronger.  Just don't forget to rest, because this happens on the days off.  The adaptation is pretty quick, do the same exercise after 48-72 hours, and you're not likely to have the same amount of soreness.   
Muscles actually absorb energy during the ECCENTRIC phase; a variety of sources estimate that they are 40% stronger than in the CONCENTRIC phase.  To get the benefits, perform the ECCENTRIC phase completely and slowly.  Most training protocols specify 2 or 3 or 4 seconds for the ECCENTRIC contraction, however, some may call for a last repetition with a 10 second ECCENTRIC contraction.  Be careful trying this, use less weight, and work with a spotter - your muscles will tire more quickly and can fail unexpectedly.

Body builders often use this to continue working longer and/or harder in the ECCENTRIC phase.  For example, you might have a spotter lift the weights to perform the CONCENTRIC contraction in chest press or biceps curl, and complete the ECCENTRIC contraction on your own.
Breathe life into a stone, quicken a rock, and make you dance
 
More and more research is showing that emphasizing ECCENTRIC exercises and movements can be helpful in rehabilitation and prevention of tendon and muscle injuries, especially chronic tendinosis that may not respond to other therapies.  One advantage is that it can both lengthen and strengthen a muscle.  If you're experiencing chronic tendon or muscle problems, talk to your doctor or physical therapist about an incorporating ECCENTRIC exercises into your rehab program, and I can help you transition into the gym.

Use can almost change the stamp of nature

You may be able to prevent injuries in the first place and avoid re-injury by using ECCENTRIC exercises to "prehab" vulnerable spots.  For example, I have several clients who are runners and athletes incorporating ECCENTRIC calf exercises into their programs to protect the achilles tendon and plantar fascia.  Early intervention may help keep you from developing chronic injuries and landing in rehab in the first place.  This applies across the board, from competitive athletes to those just beginning a fitness program.