Forefoot running reduces the rate of the initial impact that your knees have to absorb as the foot strikes the ground. However, the other side of the trade-off is that more loading is placed upon your calf muscles and Achilles tendon.
Let’s take a closer look…
Running is a high-impact activity. It’s tough on your body. There’s no getting away from that!
However, the unique characteristics of your running technique certainly have a role to play in determining how (and where) your body deals with the loading that occurs stride-by-stride.
Let’s specifically discuss the differences with a view to understanding how these two common running styles place different demands on your knees.
Let’s start by reviewing some fundamentals when it comes to the running gait cycle…
What happens when a runner’s foot strikes the ground?
The very moment your foot comes in contact with the ground as you run (or walk for that matter) is referred to as initial contact – regardless of which part of your foot strikes the ground first.
Initial contact signifies the beginning of what we refer to as the stance phase of running gait. The period during which you have one foot on the ground, supporting your bodyweight.
Stance phase can be sub-divided into two sections, with two very different goals:
1. Absorbtion – Early Stance Phase
The period from initial contact to the moment the foot is beneath the hip (known as mid-stance).
During early stance, the main goal for your body is to absorb the impact as your foot strikes the ground and your body weight is supported above.
Newton’s 3rd Law tells us: ‘Every action has an equal and opposite reaction’. This explains why we feel the impact as our feet strike the ground.
As the foot hits the ground, the ground hits us back!
The force your body experiences “hitting you back” is known as ground reaction force (GRF).
Early stance phase of running gait is largely about your body absorbing GRF efficiently – essentially turning the landing leg into one big shock absorber!
This is achieved through movements in all three planes of motion, starting at foot and ankle level with pronation and dorsiflexion, immeidately followed at the knee and hip with flexion, adduction and internal rotation.
Simply put, the more GRF the body has to deal with, and more importantly, the faster the rate of onset of force, the more stress and strain your muscles and joints have to withstand with each stride.
2. Propulsion – Late Stance Phase
This is the period from mid-stance to toe-off. Toe-off being, as it sounds, the moment the foot leaves the ground.
In fact, mid-stance is where the body’s priorities switch from shock absorption to propulsion, to help you achieve effective forward progress with each running stride.
You switch from creating flexion at key joints such as the knee and hip to absorb load, to creating powerful hip and knee extension, using your glutes and hamstrings to push your body forwards and on to the next stride.
When it comes to appreciating the difference between forefoot running and running with a heel strike, let’s focus on early stance phase.
The two videos below do a great job of demonstrating how running with a heel strike creates a very different force profile for your body to deal with, in comparison to running with a forefoot strike.
Running with a Heel Strike – Ground Reaction Force
The video below shows somebody running barefoot on an instrumented treadmill with a heel striking running technique. The treadmill measures GRF with each stride. You can clearly see the initial transient impact spike caused by the heel strike at initial contact.
This transient impact spike represents the sharp increase in ground reaction force that the runner’s body has to absorb during early stance phase.
Running with a Forefoot Strike – Ground Reaction Force
In comparison, the video below shows the difference in force profile created by running with a forefoot running technique.
The obvious difference is the lack of a prominent transient impact spike in the GRF graph.
Of course, your body has to support it’s own weight on the stance leg, but the rate of onset of this force is quite different in the two different running styles.
Let’s not forget that the knees play an important role in absorbing the force created when a runner’s foot strikes the ground. Hopefully the videos above provide a good insight into how the two different types of running technique place different demands on a runner’s knee during the absorbtion (early stance) phase of running gait.
By this logic we can resonably suggest that many runners who suffer from knee injuries such as runner’s knee would potentially benefit from moving away from a heel strike, and adoption more of a midfoot/forefoot running technique.
How to Start Forefoot Running
If in reading this, you’re tempted to start forefoot running to reduce the stress on your knees, I would advise you to make the chage gradually over 6-12 weeks, and to allow your body time to adapt to the demands of the new running style.
Those of us who remember high school physics lessons might recall being told something about forces being transferred rather than simply disappearing…
Here’s one of those real-world applications of the physics lesson!
Where we reduce the impact on your knees by forefoot running, we increase the demand placed on your plantarflexor muscles and tendons around the ankles.
This in itself is no bad thing, and a challenge that these soft tissues are created to be able to adequately meet… but not if you take them by surprise!
Here’s an example of the type of training plan I give runners to follow while they are in this transition phase of changing to a forefoot running technique: Free 12 Week Return to Running Programme
Conclusion – Should You Start Forefoot Running?
So back to the original question: Is forefoot running better for your knees?.
There’s definitely as argument to say that runners who suffer from impact related knee injuries may well find forefoot running to be a great option. I’ve certainly seen this in runners I’ve worked with over the years. I
Changing to a forefoot running technique should reduce loading on your knees, but at what cost?
The last thing you want is to exchange running related knee injuries for an Achilles tendon injury or calf strain.
In my experience, distrance runners who have problems transitioning to forefoot running are usually those who:
- Try to run too much too soon, both in terms of running distance and number of runs per week
- Adopt too aggressive of a forefoot strike and remain “on their toes” throughout stance phase like a sprinter.
If you’re a heel striking runner training for longer distances, half marathons and beyond rather than 5-10km races, you might also want to apply the logic set forth in this post, to adopting more of a midfoot running technique, or even a lighter “proprioceptive” heel strike.
There’s evidence to support the idea that simply adopting a less pronounced heel strike will have much the same outcome in reducing the intial impact on your knees.
Doing so will most likely be fore more sustainable for runners training for longer distances, and for those who are predisposed to calf issues.
Whatever you choose to do, listen to your body and over time you’ll find a solution that feels both lighter underfoot and sustainable.