• * Increase in strength in just one week (46%).
• * Bigger strength gains in 10 week training cycle.
• * Increased muscle damage vs. traditional training (sounds bad but isn't - see Max Strength Gains for more).
• * Significant increase in satellite cell content per muscle fiber (by 27%).
• * If desired, eccentric overload training can lead to greater strength without increased muscle mass.

Increasing the eccentric load in an exercise increases satellite cell content in type 2 muscle fibers.  It also increases muscle damage.  Although "muscle damage" may sound bad, it isn't - it's an important step in getting the muscles stronger (and/or bigger).  The  combination of increased satellite cell and muscle damage (among other things) leads to greater strength increases (up to the maximum possible without "enhancement").  The amount of eccentric overload, workout volume, and rep dosage required to maximize strength varies depending on the person and overall desired outcome.  Studies in eccentric overloading continue to be performed and the results should aid in refining eccentrically overloaded workouts.

Generally, exercises are performed without regard to stroke timing, and the eccentric motion is performed fastest.  For strength gains, studies indicate that the eccentric stroke range of motion should be performed for 1-3 seconds for maximum results.  To increase strength, the eccentric load needs to be increased, which in turn makes the muscles work harder each set, thereby using more energy.  For example have a person lift a 45lbs plate.  Ignoring inertia, the lifting motion requires a force of 45lbs plus (say 48lbs - the more the plus, the faster the plate moves upward).  The lowering motion requires a force of 45lbs minus (say 42lbs - the more the minus, the faster the plate moves downward).  The muscle energy will be greater for the lifting and lesser for the lowering, hovering around 45lbs (in this case 42lbs to 48lbs).  Let's change the lowering event by increasing the weight of the plate to 90lbs.  Now, the lowering motion requires a force of 90lbs minus (say 87lbs).  As can be clearly seen, the muscle energy for lowering is now much greater than before (over 2x) and varies (in this case) from 48lbs to 87lbs.  This greatly taxes the body, reducing workout time.

A bench press study consisting of three groups (eccentric, concentric, traditional (eccentric + concentric)) performed a six week training period with no difference detected between training protocols.  This yielded improved relative bench press strength similarly and significantly.  The training session was followed up by a six week "detraining" period where no workouts were performed.  Following the "detraining" period, the groups were re-tested, and only the eccentric group retained relative strength above pre-testing conditions while both concentric and traditional groups returned to baseline (pre-testing) values.  For long athletic seasons (like baseball) or when athletes may not be training for extended periods of time, trainers and coaches may want to consider eccentric training.

Increasing ligament and tendon (i.e. connective tissue) strength reduces injury susceptibility.  This is especially true for high impact or "heavy load" activities. Connective tissue cannot be strengthened using high reps and light loads - strength is increased using moderate to heavy external loading.  This is also true for connective tissue size increases (but requires long term training).  Eccentric overload training is an excellent way to externally load (and therefore strengthen) connective tissue, resulting in a stronger body (not just stronger muscles).

When a load is placed on a bone, the bone remodels.  Bone density increases, the bone becomes stronger, and the chances of bone injury is reduced.  Eccentric overload training provides superior loading to the bone (and also the connective tissue and muscles as well, strengthening them all).  As the body is strengthened, overall risk of injury is reduced.  Eccentric overload training has been shown to increase bone mineral content and bone mineral density in as little as 6-8 week sessions, especially in senior citizens.

When a load is placed on a bone, the bone remodels.  Bone density increases, the bone becomes stronger, and the chances of bone injury are reduced.  Eccentric overload training provides superior loading to the bone (and also the connective tissue and muscles as well, strengthening them all).  As the body is strengthened, risk of injury is reduced.  Eccentric overload training has been shown to increase bone mineral content and bone mineral density in as little as 6-8 week sessions, especially in senior citizens.

Managing the overload resistance during the one-or-more-second eccentric cycle typically requires full body engagement, thereby strengthening the core.  This also helps train full body engagement while performing specific exercise motions.

Research shows eccentric overload training through the full range of motion promotes flexibility much more effectively than static stretching.  For example, one study had participants with tight hamstrings performing eccentric hamstring exercises.  Flexibility improved two times better than the static stretching group.  Another 8 week study for ankle/knee/hip flexibility found a 50 percent greater efficacy using eccentric overloading, and the list goes on.

Eccentric overload training increases eccentric strength far more than any traditional strength training.  As eccentric strength is increased, so is the ability to absorb energy eccentrically without injury.

Eccentric overload training helps protect joints in a number of ways - by strengthening the connective tissue, the surrounding muscles, and promoting greater body engagement throughout the range of motion.  Increasing eccentric strength also increases eccentric contraction capability which decelerates the joint during loading and/or load repositioning (which therefore protects the joint). 

Furthermore, adjusting/reducing the concentric resistance for an exercise (especially for rehab or when joints are "twinging") reduces/eliminates joint stress, and positive exercise results can be realized where the traditional exercise would have been skipped due to joint discomfort/pain.

When comparing concentric and eccentric exercises, studies show that eccentric work results in considerably greater force production, substantial decrease in energy expenditure, reduction in heat production, and lower oxygen consumption, for both muscles and tendons/ligaments.  In contrast, heat generation increases during concentric work with a simultaneous increase in cellular metabolism resulting in greater waste production which, in turn, leads to nerve irritation and eventually, pain.