Years ago… (and I mean, ‘YEARS AGO!’) when I ran track and cross country in college, I recall doing a ton of running drills before and after practices. While some of the drills were integrated randomly, the three drills that always seemed to be a constant were, High Knees, Butt Kicks and Straight Leg Scissor Kicks.
The theory being that butt kicks helped your leg turnover and finishing kick and high knees helped to reduce, or at least minimize a shortened/shuffling gait – especially when you began to tire toward the end of a race. And straight leg scissor kicks were meant to help elongate your stride in front of your body and to stretch your hamstrings.
Now in concept, these drills make sense, as they sort of mimic running form… which is why they are still practiced today by a lot of runners and are recommended by reputable sources.
SO WHAT’S THE PROBLEM?
Before we address exactly what the issue with these drills are, it’s important to know and understand two types of movement, Active and Passive.
Active movement refers to movement that requires conscious muscle activation (ex: bicep curl) whereas passive movement refers to movement that is does not require conscious muscle activation (arm swing when walking).
This rapid knee flexion/extension of butt kicks is meant to train a runner to develop a fast kick and leg turnover. Muscularly speaking, this drill primarily focuses on the hamstrings. However, this aspect of the running gait is largely passive. Therefore, by performing this drill, the runner is taking a passive movement and turning it into an active one (e.g., muscle activation required). While there may be some value to this drill from a neuromuscular standpoint, it is largely invalid.
What To Do Instead…
It is advised that a drill such as strides would be more beneficial as the drill exactly mimics the body during a sprint but does not ‘convert’ a passive movement to an active one.
This drill is commonly performed to teach a runner how to “drive with the knees” and to focus on sprint form. Like the butt kick drill, knee flexion while running (or walking) is primarily a passive movement. This drill overemphasizes the hip flexors. Also like the butt kick drill, the high knees drill takes a passive movement and turns it into an active movement. If there is one part of the body that typically does not need to get shortened, it is the hip flexors!
The one caveat to this is if you run up very steep hills/steps where excessive hip flexion is an active movement (of if you’re a hurdler or steeplechaser!).
What To Do Instead…
As high knees are often used as a form drill, focusing on overall body strengthening (especially the ‘core’) and progressively building endurance and intensity-based runs so that one’s form does not break down substantially during runs is advised. Additionally, focusing on other form ‘drills’ such as shortening the forward aspect of your stride and keeping our head up will likely help much more than high knees.
STRAIGHT KNEE KICKS
As noted previously, straight knee kicks are often used to ‘help’ a runner extend their stride in front of their body (not sure why you would want to do this). So while we could stop right here, the secondary reason why this drill should go the way of the dodo is because it puts excessive braking force on the hamstrings.
Running with good form already forces the hamstrings to act as a braking force and it’s one of the biggest reasons for hamstring pain/injury – so why would you implement a drill that would increase the chance for this?
Lastly, as you can see from the video, you also tend to look a tad bit ridiculous – but I guess I’ll save that issue for another blog post 😉
What To Do Instead…
Nothing. There is no need to focus on elongating your stride in front of your body. If you’re performing this drill for the purpose of eccentrically stretching your hamstrings, stick to non-ballistic movements such as single leg deadlifts.
While the aforementioned drills appear to mimic running form, they might do more harm than good because of their lack of practicality and increased chance for injury due to their ballistic nature and excessive eccentric braking requirement. In the case of high knees, ‘over tightening’ the hip flexors may also lead to injury or at least compensated posture and form.
Primary take away: There is no need to train a passive movement in isolation and make it an active movement.
Weyand PG, Sandell RF, Prime DN, Bundle MW. “The biological limits to running speed are imposed from the ground up.” J Appl Physiol (1985). 2010 Apr;108(4):950-61. doi: 10.1152/japplphysiol.00947.2009. Epub 2010 Jan 21.
Rick Prince is the founder of United Endurance Sports Coaching Academy (UESCA), a science/evidence-based endurance sports coaching education company that certifies running and triathlon coaches.
To learn more about our Running Coach Certification and to get a code for $50 off, click here!