Muscles tight, no matter how much you stretch...

What if your tight muscles weren't really tight after all? What if flexibility, or lack of, wasn't your problem?

If you are constantly stretching your calves (or quads, hamstrings, glutes, ...) for no change. Try strength training instead. If you think about it, it makes perfect sense. Weak muscles have to constantly work harder. Weak muscles fatigue quicker. No wonder they tighten up.

Try adding 2 -3 strength sessions a week for a month or so and notice the improvements. Not only will the 'tightness' disappear, but your running performance should also increase too.

If you are new to strength work, start light and progress. But the end goal is low reps, heavy weight. Runners do enough endurance work whilst running, strength endurance work in the gym (high reps) is just doubling up.

Pushed for time? You don't need to do an hour. A quick 15-20 minutes slotted in between runs 2-3 times a week will still get results, especially if you're new to this. At bare minimum, just work the tight/weak muscle, but ideally try choosing 3-4 exercises that target the main running muscles; calves, quads, hamstrings and glutes. 2-3 sets of 6-10 reps (70-80% 1 rep max).

For the actual tight muscle, include some slow heavy eccentric exercises. This lengthening under tension will build muscle whilst also stretching it out. Bonus!

If you can't get to a gym, get creative at home. Initially, body weight may be enough, especially single leg. (remember, running is a single leg exercise, it makes sense to train this way too). But pretty soon you must add weight to progress the training stimulus. Once 10-12 reps is too easy, add weight and reduce reps. And repeat. Use a backpack full of books, water bottles or buy some dumbbells.

Just make sure to monitor your body's response to the extra training load. Try separate hard run sessions from the strength workouts. And take in extra carbs and protein to promote growth and recovery.

The other possibility is you are running too far (or too fast), beyond your current fitness capabilities. Or too often, not allowing adequate recovery between runs. Consider dropping back a little temporarily to find your sweet spot, then build from there. And remember, good nutrition and sleep are vital for good recovery.