I'm 63. Running 30 sec hill repeats 3 days ago up a 6% grade. I've had great success w hill repeats - builds strength & speed, not likely to cause an injury.

On repeat #4 I feel a very slight right ham strain but I do #5 anyway (classic denial symptom) and can feel it was something but likely a niggle (another classic denial symptom). I quit the repeats and switch to 3' BIKE hill repeats - I just do 3 of them even though they are completely (really!!) symptom and pain-free. Feels fine that afternoon, I ice in the evening.

Next day is a Rest day. I try a short jog (20 yards) that next morning - definitely a strain, but seems very slight.

Next day is an added Rest day. It seems to hurt when I am motionless and is 100% ok when I walk!

Today, I try hamstring curls and then bridges - both w a Swiss ball - ZERO pain or symptoms.

Am I healed? In my past (more severe) ham strains those ham-curls on the Swiss ball have been terrific in aiding my recovery but not this quickly. Should I return to workouts?

How can an exercise that isolates an injured muscle group not cause even discomfort in that group?