To reduce the rate of muscle loss that begins at 30 and to stave off muscular imbalances that older athletes experience, runners must focus on strength training.

Vern Gambetta, a renowned coach and consultant to professional athletes, says runners don't need to spend a lot of time on strength but that consistency over time is key. Gambetta recommends starting exercises at body weight before adding resistance, and working with a strength coach to guide proper form.

1. Single-Leg Squats

Start with one set of 10 reps on each leg; progress to two sets of 20 reps.

"Squats are all-purpose exercises that require no equipment and can be performed anywhere," says Jeff Horowitz, author of Quick Strength for Runners. They improve the strength of the lateral stabilizers and quads. Running doesn't do much to improve these muscle groups, but if they're weak it can lead to problems.

2. Step-Ups

Start with three sets of six reps on each leg; progress to four sets of 10 reps.

These are a key exercise to help runners increase strength in hamstrings and glutes.

3. Chin-Ups

Ian Nielson, strength coach for the Mammoth Track Club, recommends including a "body-weight pulling movement," like a chin-up, every other workout. It will help with posture and improve arm carriage.