LOWER LIMB FORCES WHILE RUNNING
, by Alexander Davies, 5 min reading time
Running and new runners running is on the rise as its inclusive, cheap and accessible without the need to arrange a court or organise a team (which in the current climate isn’t even possible). Therefore, it is worth understanding what effect and stresses these exercises have on our bodies and limbs.
The 2020 pandemic and its associated restrictions has caused many to cherish their time spent outdoors and exercising. This has seen the eruption of home workouts, running and cycling which is fantastic for health and wellbeing.
It’s no surprise that running and new runners running is on the rise as its inclusive, cheap and accessible without the need to arrange a court or organise a team (which in the current climate isn’t even possible). Therefore, it is worth understanding what effect and stresses these exercises have on our bodies and limbs.
While standing, walking and running our legs are exposed to varying degrees of force.
In physics, force is defined as the product of mass and acceleration, for our purposes, we can define force as the amount of stress through our bodies by impacting the ground while walking/running.
The reason that the vertical forces are greater in walking and running than they are when you are standing still is that; in standing, the vertical force has just to balance your weight. However, in walking, and to a more extreme case in running, the force has to support your weight and produce a change of momentum as you land. Changing the downward motion to an upward motion for the following stride.
When you run and your speed increases, you achieve this by increasing the length of your stride and the frequency of the movement of your legs. Both legs rotate as you run and the centre of gravity of your body also moves up and down by a few cm during each stride in both walking and running.
In walking this force would be up to 1.5 times your body weight while in running it might increase to between 2 and 3 times your body weight.
Force has the characteristics of quantity and quality. Quality is what has previously been loosely explained and can also vary from person to person with factors like mobility, biomechanics and weight.
Quantity is the other arm of the equation and in the context of running is often referred to as ‘training intensity’. Many new runners often experience injuries after an increase in the amount of running they’re doing whether that be in frequency, effort or distance.
When this increase is not applied gradually, the tissues do not have adequate opportunity to acclimatise to the higher-level forces and often results in a range of injuries. With this in mind it’s no surprise that lower leg and joint pain is a common complaint among runners, especially new runners given the key roles these muscles, tendons and bones play while running.
Several other factors can also contribute to force related running injuries from diet, recovery routines to running form and shoes. Many of the lower limbs affected are listed below, when these and complimenting areas are weak, tight or overworked, they become vulnerable to injury:
Foot – Great debate rages as to whether heel striking, or forefoot running are better or worse for impact reduction and each have their own trade-offs further up the leg. Nevertheless, with the foot being the first point of contact with the ground from the stride impact it takes a large proportion of the force and can be susceptible to sprain, strain and stress fractures.
Calf & Achilles Tendon – These work together to help generate the force that pushes you off the ground with each step. Without regular mobility and strengthening exercises and being placed under increased loads and overuse these can be susceptible to strains, pulls, tears and tendinitis.
Shin – After the foot the shin is second to absorb and dissipate impact from running strides. The most frequent injury referred to is shin splints and while many different types of shin pain fall under this catch all term, most shin splints occur when there is more stress on the tibia than it can handle.
The best form of treatment is prevention, here are some tips to prevent most of the aforementioned injuries:
- Strength training; a wide range of resistance exercises can help strengthen the muscles and tendons to help them cope with the increase in load from running training intensity increasing.
- Foam Roll; a method of home massage, this can stimulate the break-up of tissue to accelerate recovery and release muscle tightness. Recommended to be done daily.
- Stretch; the better your mobility and soft tissue flexibility the less susceptible to injury you will be, with the ability to complete a better range of movement comfortably.
If you’ve unfortunately missed the prevention stage and have suffered an injury, the first point of call would be to seek professional medical advice. Following that most soft tissue and impact injuries can be treated with the following:
- Stop Running; Don’t run until you can do so pain free, else you are at risk of prolonging and worsening the injury. Alternative exercises like, swimming and cross training can be a good, less impactful reintroduction to running.
- Ice; Apply ice for 15 minutes five times a day, this to increase blood flow to drive fresh oxygenated blood through the injured limb to flush toxins and help soft tissue repair.
- Compression; Use compression when not icing to help increase blood flow and drive fresh oxygenated blood. However, it is imperative to not become reliant on the joint support or compression sleeve and strengthen the muscle and tendons themselves along with those complimenting the movement.
