Getting to the core of the matter

Tonight's workout:
2.5 miles run/walk
2x 30sec planks
2x 20sec side planks
2x 1min hip bridge
2x 20 rep clamshells

The most common strength deficiency (and the one that tends to result in injuries) is in the posterior chain and hips... my guess because we all do a lot of sitting.   Plopping down on your ass all day isn't really good for anyone... and even if you are active for 2 hours a day but then sit for the remainder, you're still sitting way too much.  Sitting also disengages your stomach muscles, slumping and slouching over our computers, which means our abs are the other weak point for most.

Runners and cyclists have the added issue of constantly moving in the forward direction (as opposed to a soccer player, whose movements include lateral and such), making the sagittal plane the strongest, and frontal and rotational ones weaker.

My suggestion typically for anyone looking to stay injury free - focus your crosstraining efforts on buiding glute and hip strength, including side-to-side movements, and working your core muscles as a unit.

There are any number of good hip workouts available on line, some specific for runners like this video.

I have become a big proponent of non-isolation moves for core work (sit ups, I'm looking at you).  The core (and specifically I mean back, abs, hips, glutes) works most effectively when all parts are humming along together.   And so you should train your core so that it's engaging and firing on all cylinders.  Asking one part to work while the rest are asleep, to me, seems like a recipe for muscle and strength imbalances.  

In simple terms, if you think about what the core does, the best exercises are then those that challenge the core to work hard/harder at that job.   The set of core muscles support the spine through normal movements - a plank works effectively because you're basically using gravity to add a force, making it more difficult for the core to keep the spine in a neutral, supported position.    If planks are too easy for you, add in difficulty by either reducing the number of contacts with the floor (raise a leg) or movement (like this).

Other good core exercises, with links to instructions/videos:
Pallof press  (engages the core to withstand a force wanting it to rotate)
Stir the Pot (a plank - with an unstable surface AND movement, incredibly difficult)
Bird Dog

Next up, why you should use a standing desk.  :)