The phrase "too much of a good thing" can be applied in some shape or form to lots of things (depending on your definition of "good").
Too much alcohol - makes you feel terrible, too much pudding - also makes you feel terrible, too many late nights and parties - terrible; and you can add to this list "exercise".
Wait - This is NOT an excuse to just do the odd bit of exercise and me saying "you don't want to do too much - it's bad for you." That's not what I'm saying at all.
I'm talking about issues caused by repetitive movements. Here are a few tips to make sure that you don't make exercise "a bad thing".
1) Off ya bike!
Imagine in your head a perfect posture. Head upright, spine in a neutral position, hips below shoulders. Then imagine your position on a bike. Far from this perfect posture correct? I'm not saying "never cycle" but if you want to repeatedly compromise your bodies natural shape and form then cycle every day. If you DON'T, then get off of your bike and add variety to your cardio. Also add in corrective resistance work and mobility work between bike sessions.
2) Run on the other side of the road
Most roads are cambered so if you do a lot of road running try to run on different sides of the road in order to avoid repetitive strain issues from an unbalanced running style. It's as simple as that!
3) Add resistance
Making resistance work a part of your weekly gym schedule with have multiple benefits to aid your bodies recovery and general robustness: 1) You'll be stronger and more efficient when it comes to your cardio sessions, 2) You'll be stronger and more robust when it comes to injury avoidance, 3) You can un-do some of the repetitive strains added to your body by countless hours of cardio. 4) You'll give your body a break from the usual cardio and offer it an alternative stimulus.
4) Find a kinder surface
If you're a regular runner then road running can be very unkind for your joints. try to add variety and find a kinder running surface such as an athletics track.
5) Run correctly
Most people think they can run because they can move at a walking pace and then do some movements that make them move a bit faster. There is in fact a lot more technique to running than many people understand. If you intend of running regularly you should seek the advice of an experienced running coach. Not only will this help you to avoid injuries but it should also make you more efficient. You wouldn't buy a car and just "give driving a go" as you'd probably damage it. So why would you take the same risks with your body; an object that can't be replaced when damaged?
1) Pull more than you push
Most things we as humans do are in front of us and require us to hold our arms in front to do so; driving, eating, typing etc. This often causes a shortness in the anterior muscles (front side of the body) causing a rounding of the shoulders and neck. Try to un-do the everyday tensions by focusing on "pulling" work in the gym far more than you do "pushing" work. For people that perform push ups and sit ups every morning.. stop it!
2) Move freely
It's important that you allow the body to move as it's designed to. Try to include a variety of movements in all sessions. As well as your standard push and pull work make sure that you rotate, hinge, lunge and crawl or climb. Don't be limited by resistance machines and conventional exercises, use your own body, move naturally and incorporate elements of play into your exercise regime.
3) Don't train the same muscle groups consistently without sufficient rest
By not allowing sufficient rest for muscles your body will not be able to repair, adapt and grow. If you have a set gym routine that you cover every time you're in there then this needs adjusting. If you're not sure how to do this then see a professionals help and ask them to design your gym programmes in 6-8 week blocks and then re-visit them for a new set,
4) Train the body equally
Most people (males especially) like to train what they can see. Usually their chest, abdominal area and biceps are the main focus week-on-week. Training with this as your sole focus not only leaves the symmetry of your body all out of whack, but also causes additional strain for areas of the body that are weaker and are forced to operate in an alternative, incorrect way in order to compensate for the weakness. For example, neglecting your legs and glute muscles may lead to back pains due to a weakness in that area.
5) Train limbs individually
It can be tempting to stick with resistance machines or barbell work for the majority of your resistance work. However, often these exercises to do not highlight areas of weakness or imbalance in terms of strength or range of movement. It can be hard to definitively say where the majority of the effort is coming from. For these reasons it's important to regularly train single limbs, uncover areas of weakness and imbalance between the left and right side of your body and then address these issues.
Foam roll and stretch
Everyone (in my opinion) should foam roll and stretch regularly. Even if you're not a regular exerciser you need to undo the unnatural confinements, positions and strains that your lifestyle imposes on you. We're not designed to be sedentary; we should move be mobile and be free. Help your body out and give back regularly.
Ultimately, it's about finding a good balance that suits both your lifestyle and your own personal rate of recovery. Listen to your body, think prevention rather than cure when it comes to injury and recovery, don't put all of your eggs in one basket and don't have "too much of a good thing."