Spice it up! Implement variety to run faster and stay healthy

As runners, we have all experienced the high amounts of stress that distance running puts on our bodies. In a single stride, your body sees impact forces of 50 to 80+ body weights per second – just check out your Pod’s rate of impact metric! Multiply that impact force by 10,000 steps for a typical 5 mile run. That’s a lot of stress!

One way to reduce the potentially harmful effects of repetitive stress from running is to introduce variety to the stress your body sees during training. Exposing the body to variety in the stress helps spread the accumulative stress of training over a number of structures instead of just one. This is key to reducing injury and improving performance.

Here are a few approaches that I use to introduce variety to the stress my body sees during ultra-marathon training:

#1. Run in different shoes. This is a technique that I started doing a few years ago, with great success. Wearing different shoes each day in training exposes the body to subtle differences over your training cycle. There is no need to do anything too dramatic here. Even small differences in shoe specs (i.e. amount of cushioning, heel-toe drop, arch support, toe box) and rotating between just two shoes, will change the mechanical function of your foot and influence gait mechanics up the chain. Importantly, track your shoe mileage (easy and automatic with the Pod’s Shoe Odometer!) and know when to replace them! Never wait until you have shin splints or knee pain to replace your shoes with a new pair. (See Dr. Steve’s blog on how Pod metrics, especially rate of impact, change over the course of your shoes’ life).

My current set of “smart” shoes (with Pods!) in the rotation. This is a little overkill on “variety,” but you get the idea!


#2. Polarize training effort. This means run fast on hard days, run slow on easy days. This is important because your running mechanics change with different speeds of running. One example of this that you may have observed in your Pod data: when running faster, your ground contact time tends to decrease while your rate of impact might increase. Polarizing your training paces will not only reduce your risk for injury, but also improve your performance making you run faster at races. Win – win!

#3. Cross train.Ugh!” – the reaction most runners have when this is suggested to them in PT. Cycling, elliptical or swimming may seem like a drag but they are great strategies to provide an aerobic stimulus to the system without the high impact. I also encourage runners to regularly participate in activities that involve frontal plane motion (i.e. moving side-to-side) and quick cutting movements like basketball, soccer, skiing, etc. Muscles that stabilize motions during these activities, especially the hip and ankle muscles, tend to be weak and fatigue quickly in runners who only run. These cross training activities are a beneficial and can be a fun way to introduce variety into training!  P.S. You can get some really interesting Pod data during a pick-up game of basketball!

I think cycling with friends makes this activity much more bearable!


#4. Run on different surfaces and in different conditions.  Run on roads, trails, flat and hilly surfaces. It’s easy to see how these changes can introduce variety to your mechanics and overall stress from training. As a general rule, I never do the same run or workout twice within a 10 day period.

Implement variety into training to stay healthy and get fast!

Happy Trails!

Author: Jackie Merritt

Jackie is an accomplished ultra-runner and an avid MilestonePod data fan. She has a Doctorate in Physical Therapy and a PhD in Biomechanics. She lives and trains in Atlanta with her husband Jeff and the Yeti Trail Runners. When not running, Jackie works as a PT and research scientist at Emory University School of Medicine. Jackie also runs for Hoka One One and NATHAN Sports.