How strong is the human body?

The human body is amazing & it is surprisingly very strong.

Many people are worried that they will hurt themselves with innocuous activities and this can lead to fear, anxiety and avoidance of certain things.

Is this a legitimate fear though? Just how strong is the human body?

This is precisely what we are going to show you in today’s article. We will be looking at how strong your Achilles tendon is and how much load it takes to break your Femur (thigh bone) and much more. I think that you will be surprised by just how strong we are and hopefully this will enable people rather than disable them through fear of hurting or damaging themselves.


What load can your Femur take before breaking?

String femur

People do break their femurs but the loading is usually sideways rather than vertical and this sideways impact is the weakest direction. The femur is at its strongest down its length but it is not so strong across its length, which makes sense based on its function. It has been shown that the femur is able to tolerate between 1.5 to 2 times the load down its length than across (Keyak et al 2000). To fracture the femur by loading down its length, the load has been measured at 20 times your body weight (Van Rietbergen et al 2003).


What load can your Achilles tendon take before snapping?

Are you worried about snapping your Achilles tendon and think that running or other activities can just snap the tendon from scratch? Don’t be so worried the tendon is crazy strong, in fact, it is the strongest tendon in the human body. Maffulli et al (2004)  found that every square centimetre of your Achilles tendon can take between 500kg to 1000kg. So when you think that the Achilles is on average 15cm long and 6.8cm wide, this roughly gives an average total square centimetre amount of 102 square centimetres and this equates to a total average load of between 51,000kg and 102,000kg!!!!!!


What load does it take to lengthen your ITB (Iliotibial band)?

ITB stretch

Ever been told that your ITB is tight and you need to stretch it? Can you actually lengthen it and if so how much load would it take to achieve this? In a study by Chaudhry et al (2008), they found that it takes 925kg to stretch the ITB by just 1%! So it looks like this ‘ITB’ stretching is not actually going to lengthen your ITB. However, you may be lengthening the muscles at the hip, which attach to the ITB so maybe all is not lost.


Your knee is the weight-bearing joint of the body, so how much can it take when we jump?

When we jump the force through our knee (Tibiofemoral joint) has been measured up to 9 times your body-weight, which is pretty impressive and highlights the relevance of weight loss in knee pain sufferers (Cleather et al 2013). There are obviously lots of other factors that influence the loading in the knee joint and one of these is something called tibial varus, which is when your shin bone is curved creating a bow-legged appearance. It has been shown that just a 3 to 5° of tibial varus increases the force on the medial (inside) tibiofemoral compartment of the knee by 50% (Wong et al 2011).


How much force does the Hamstring generate when sprinting?

Hamstring strains are common in sprinters so clearly they must be taking an awful lot of load but how much exactly? Schache et al (2012) found that sprinting produced a peak Hamstrings force of 8.5 times your body weight. The good thing is that you can strengthen your hamstrings and build up their load capacity and this has been proven to reduce hamstring injury risk. A great exercise to strengthen your Hamstrings is Plyometric Nordic Hamstring curls.

How much load does the lower back take in normal daily activities?

Weak back

People think that the lower back is fragile and easily injured but as we have seen so far in this article the body is very resilient and this is no exception in the spine. In a study by Rohlmann et al (2014), they measured a force of 1650 Newtons when lifting just 10.8kg from the floor, which is 168kg equivalent load. Imagine what the load would be with the 501kg deadlift world record!! So don’t be scared of lifting with your back and rounding it, I even give some of my Physiotherapy patients at my Stoke-on-Trent clinics, certain exercises such as Jefferson curls to get them stronger but to get over the fear of lifting and bending their backs.



So you get the drift of the article the body is able to easily handle high loads. Now you may disagree with me thinking that you have injured yourself with something not that heavy or hard but the chances are that you already had the injury asymptomatically beforehand believe it or not. Another reason can be down to doing something that you are unaccustomed to causing you to overload what you personally can tolerate.

As long as loading is progressively done over time then the human body easily adapts to what is being asked of it. The reality of injury and pain is to not shy away from load but build into it slowly without irritation and your body will be able to handle more and more making it even harder to overload. If you think ” I might slip a disc” remember that you are not that weak, discs don’t slip they are rigid, tough and very hard to move. If they were that soft and squidgy then we would have no stability and be wobbling like Mr soft down the street!

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If you need any further information or would like to book an appointment then call Hawkes Physiotherapy on 01782 771861 or 07866 195914.

  • Chaudhry, Hans, et al. “Three-dimensional mathematical model for deformation of human fasciae in manual therapy.” The Journal of the American Osteopathic Association 108.8 (2008): 379-390.
  • Cleather, Daniel J., Jon E. Goodwin, and Anthony MJ Bull. “Hip and knee joint loading during vertical jumping and push jerking.” Clinical biomechanics 28.1 (2013): 98-103.
  • Keyak, Joyce H. “Relationships between femoral fracture loads for two load configurations.” Journal of biomechanics 33.4 (2000): 499-502.
  • Maffulli, Nicola, Pankaj Sharma, and Karen L. Luscombe. “Achilles tendinopathy: aetiology and management.” Journal of the Royal Society of Medicine 97.10 (2004): 472-476.
  • Rohlmann, Antonius, et al. “Activities of everyday life with high spinal loads.” PloS one 9.5 (2014).
  • Schache, Anthony G., et al. “Mechanics of the human hamstring muscles during sprinting.” Medicine & science in sports & exercise 44.4 (2012): 647-658.
  • Van Rietbergen, B., et al. “Trabecular bone tissue strains in the healthy and osteoporotic human femur.” Journal of Bone and Mineral Research 18.10 (2003): 1781-1788.
  • Wong, Jowene, et al. “Predicting the effect of tray malalignment on risk for bone damage and implant subsidence after total knee arthroplasty.” Journal of Orthopaedic Research 29.3 (2011): 347-353.

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Online Physiotherapy

Put simply this is Physio done via either telephone or video over the internet. Skype and facetime are examples of this.

Contrary to popular belief online physiotherapy can be very effective and it can help the same injuries that face to face physio can help. I have helped many people with injuries such as disc prolapses, tennis elbow, neck pain and much more).