A study from Virginia Tech shows that super slow training can help older people become very strong.
You can't become very strong just by exercising. To strengthen a muscle, you have to exercise it vigorously enough to make it burn and hurt. The burning damages the muscle and you feel sore on the next day. Then when the muscle heals, it is stronger than before it was damaged. When the soreness goes away, you are ready to take another workout that makes the muscle burn.
This study shows that moving a weight very slowly in sets of ten causes the same amount of damage as moving a much heavier weight rapidly, and causes the same type of muscle damage. Lifting lighter weights slowly is far less likely to cause injuries than heavy lifting. This is particularly important for older people, since they take longer to heal. You can become just as strong using the slow lifting technique, and you are more likely to stay injury-free.
Effects of regular and slow speed resistance training on muscle strength. Journal of Sports Medicine and Physical Fitness, 2001, Vol 41, Iss 2, pp 154-158. WL Westcott, RA Winett, ES Anderson, JR Wojcik, RLR Loud, E Cleggett, S Glover. Winett RA, Virginia Tech, Ctr Res Hlth Behav, Dept Psychol, Blacksburg,VA 24061 USA