I have been stepping up my training for the Spring/Summer races that I have planned. In a typical speedwork/interval workout I have been starting off with easy running, then doing my speed work, intervals, etc, and then following that up with some easier running at the end of the particular training session. So needless to say I have some heavy legs by the end of my training session.
I have noticed that my left knee has felt a bit tender when doing the final portion of my easy paced run which I use for my cooldowns. I suspected that this is due to fatigue and a change in my stride.
I came across a recent study that discusses this exact topic. By the end of the run done by the study there was an increase in Vertical Ground Reaction Forces. What this means is that runners might start off their run striking fore-foot or mid-foot and then when fatigued switch to more of a heel strike. .
A heel strike could lead to a braking action during each strike. Runners might be aware of this when they feel their stride is off or there might be pain or tenderness or soreness in an area where they do not usually feel pain or tenderness, and they no longer feel as fluid.
To combat this in my cool downs I have done four things that may help you with maintaining proper running form while fatigued. Here a few tips I have used that seem to help with running form when fatigued.
1) I am more of a mid-foot strike runner. As soon as I feel I start “hitting the ground” with more impact I speed up. I know many programs employ an easy paced run, which is what my longer cool downs 10-20 minutes are for. However, once I feel any tenderness, or soreness creep on I will speed up if it means running my easy pace a little faster than I should run. Most of the time that clears it right up. I am also not talking running back at your fast pace. In my case for example, I ran yesterday and when doing a 15 minute easy pace cool down felt uncomfortable so I increased my easy pace by about 10 seconds per mile and I truly felt my running gait become more fluid and less jarring.
2) Try to focus on landing lighter. There was a recent publication talking about how runners should try to land lightly to reduce the ground reactions forces. During this time of fatigue this is a great time to work on incorporating this into your running.
3) Another tip is to listen to what your body is saying. Do not adapt the “No pain no gain” mantra. Trust in your training. If you have been training hard cutting back a little is ok. Sometimes less is more. For example, on one of my previous runs I was doing a 15 minute easy paced cool down following some speedwork. By around the tenth minute I started to really get some tenderness in my left knee. I knew I was no longer running smoothly and was starting to heel strike. I could have pushed and finished those final five minutes, but instead I simply stopped running. Those five minutes were not going to make me a better runner, and certainly had I pushed possibly lead me to an injury. If your body is telling you to stop, then stop.
4) Choose the correct sneaker. If you find you are striking with your heel you may benefit from a running sneaker with a lower drop. Drop is basically the difference in the height from a sneakers heel to the forefoot of the sneaker
I hope these tips help you in your training and fitness. Happy running!