Benefits of eccentric (negative) training

The eccentric part of an exercise is the part when the muscle is lengthening while under tension (contracting). The benefits of this are twofold:

1. much better for muscle hypertrophy, and
2. improves tendon strength and helps injured tendons to heal.

During the eccentric part of the exercise, the muscle is trying to contract at the same time as it is lengthening...this causes more significant muscle tearing, hence bigger muscles as the muscles rebuild and adapt to the excessive stress placed upon them.

There has also been significant research to suggest that negative reps will help with tendon strength and also with repair of injured tendons. If you have an achilles tendinopathy, tennis elbow or any other chronic or acute injuries that involve the tendon attaching muscle to bone, you should definately explore the possibilty of doing eccentric work ie. heel drops for achilles etc.