Quick Facts:
- Older runners are more susceptible to multiple running injuries per year than younger runners.
- Biomechanically the greatest changes seen in running style are: Reduced overall knee flexion, reduced stride length, and increased running cadence.
- Running more than 30 miles per week and longer distances increase the risk of a running injury
- Achilles Tendinopathy is the most common running injury for older runners
- Strength training can reduce injury risk by 50%, but stretching has not been found to prevent injuries.
How do running kinematics and kinetics change with age?
We know that our running gait changes significantly as we age. The most distinctive differences are that older runners run with a higher cadence and lower step-length compared to younger runners. Given that running speed is the product of step-length and cadence, and that our pace decreases as we get older, we would expect to see a decrease in either one or both of these parameters. However, at both self-selected and controlled speeds, we see a significantly higher cadence and lower step-length in older compared to younger runners, even when older and younger runners are asked to run at the same running speeds (Bus, 2003).
In keeping with a reduced stride-length, older runners also exhibit increased knee flexion (bend) when the foot strikes the ground. We also know that older runners exhibit reduced knee flexion and extension (bending)range of motion compared to younger runners (Bus, 2003; Fukuchi and Duarte,2008). This is something that all older runners should be aware of as reduced knee flexion is a key risk-factor for tripping and falls in older age (Benson et al., 2018). Furthermore, a recent study in 2017 found that when running faster, older runners have greater hip adduction range of movement as well as increased pelvic drop compared to younger runners (Kulmala et al., 2017).
The forces experienced by the body during running also change as we grow older, and as stride-length decreases, so too do the vertical ground reaction force and the peak propulsive force (the antero-posterior component of the ground reaction force that acts to drive you forwards as you push-off the ground) (Bus, 2002; Karamanidis and Arampatzis, 2005; Fukuchi et al., 2014).
Do we know why these changes occur?
Older runners have reduced muscle strength, decreased joint mobility, reduced shock-absorbing capacity, and reduced tendon and ligament elasticity compared to young runners (Kim et al., 2016). In short we become weaker, stiffer and less able to tolerate load as we age! It is this degeneration of musculoskeletal function that causes the gait-related changes described above and the higher injury rate that is observed in old compared to young runners.
Of particular note, the plantar-flexor muscles (the muscles that you use to go onto your tip-toes and include the calf muscles) contribute extensively to forward propulsion. Reduced ankle plantar-flexor power is associated with reduced stride-length, reduced running speed and reduced propulsive ground reaction force - all gait-related changes that are observed in old compared to young runners as were described above (Devita et al., 2016). Ankle power during running can reduce by up to 47.9% between the ages of 20 and 80! Older runners seeking to maintain stride-length and thus slow the age-related decline in performance would certainly benefit from including strengthening of the ankle plantar-flexor muscles in their programmes.
Do older runners get injured more or less than younger runners?
Older runners are more likely to succumb to a running related injury than younger runners and also to experience multiple injuries in a year. Older runners also suffer from different injuries compared to younger runners. Older runners are more susceptible to hamstring, calf, and Achilles tendon injuries, whereas younger runners are more prone to lower leg and knee injuries such as medial tibial stress syndrome (MTSS) and iliotibial band syndrome (ITBS) (Willy and Paquette, 2019).
Achilles tendinopathy is the most common injury in older runners (McKean et al., 2006;Matheson et al., 1989), and is attributed to reduced plantar-flexor strength and reduced stiffness of the Achilles tendon in old compared to young runners (by 17%) (Stenroth et al., 2012).
Older runners are more likely to run longer distances, such as half-marathons and marathons. Whilst recovery is important for runners of all ages, an older runner’s musculoskeletal system takes longer to repair and adapt than a younger runner’s body. Males and those running more than 30 miles per week are at higher risk of injury amongst older runners (McKean et al., 2006).
What can I do to stop or delay the onset of these biomechanical changes?
Running is great for overall cardiovascular fitness as we age. However running alone is insufficient to stop a decline in muscle strength or prevent injury related to running, and a well-designed exercise programme should be included in the training schedule of the older runner (Korhonen,2009). A recent study found that a 12 week HIIT programme for older adults improved gait, balance, and falling risk (Jimenez-Garcia et al., 2019).
What: Ankle plantar-flexor strengthening
Why: Reduced ankle plantar-flexor strength is a risk-factor for Achilles tendinopathy, the most common injury in older runners. Ankle plantar-flexor strength declines with age and is important for forward propulsion and therefore for maintaining running performance as we age (Willy and Paquette, 2019).
How: Exercises to improve the load capacity of the calf musculature and Achilles tendon e.g. calf raises. Exercises should be slow and heavy, for example 3-4 sets of 6-8 reps and 2-3 times per week to have the greatest impact.
What: Quadriceps strengthening
Why: Quadriceps strengthening has been shown to improve the quality of articular cartilage at the knee in patients following knee surgery, and 18% of adults in England over the age of 45 have some form of knee osteoarthritis.
How: Step-ups are simple and effective exercises for targeting the quadriceps, and are also beneficial for balance and control. Exercises should be progressive, for example starting with body-weight, 3-4 sets of 8-10 reps and 2-3 times per week
What: Quadriceps and hip flexor mobility
Why: Sitting all day at a computer causes shortening of the hip-flexors and quadriceps, which can lead to decreased stride-length. Stride-length decreases with age and so focussing on factors that are associated with decreased stride-length are worthwhile.
How: A hip flexor stretch (similar in position to a long-lunge) targets both quadriceps and hip flexor mobility. Aim for a dynamic movement where you move slowly backwards and forwards into the stretch. Do this for 1-2 minutes per leg.
References:
Bus, S.2003, Ground reaction forces and kinematics in distance running in older-aged men, Medicine and Science in Sports & Exercise, Vol. 35, No. 7, pp.1167-1175.
Devita, P., Fellin, R., Seay, J., IP, E., Stavro, N., & Messier, S. 2016, The relationships between age and running biomechanics, Med. Sci. Sports Exerc,Vol. 48, No. 1, pp. 98-106.
Kim, J. Lee, Y., & Yi, H, 2016, Gradual downhill running improves age-related skeletal muscle and bone weakness: implication of autophagy and bone morphogentic proteins, Experimental Physiology, Vol, 101, Vo. 12, pp.1528-1540.
Willy, R., & Paquette, M. 2019, The Physiology and Biomechanics of the Master Runner, Sports Medicine and Arthroscopy Review, Vol27, No.1,
Benson, L. Cobb, S., Hyngstrom, A., Keenan, K., Luo, J., & O'Connor, K. 2018, Identifying trippers and non trippers based on knee kinematics during obstacle free walking, Human Movement Science, Vol 64, pp. 58-66.
McKean, K., Manson, N., & Stanish, W., 2006Musculoskeletal Injury in a masters runner, Clinical Journal of Sports Medicine, Vol. 16, pp. 149-154.
Fukuchi, R., & Duarte, M. 2008, Comparison of three-dimensional lower extremity running kinematics of young adult and elderly runners, Journal of sports science, Vol. 26, No. 13, pp. 1447-1454.
Kulmala, J., Korhonen, M., Kuitenen, S., Suominen, H., Heinonen, A., Mikkola,A. et al. 2017, Whole body frontal plane mechanics across walking, running, and sprinting in young and older adults, Vol. 27, pp. 956-963.
Karamanidis,K., & Arampatzis, A., 2005, Mechanical and morphological properties of different muscle–tendon units in the lower extremity and running mechanics: effect of aging and physical activity, Journal of Experimental Biology, Vol. 208, pp. 3907-3923.
Fukuchi, R., Stefanyshyn, D, Stirling L., Duarte, M., Ferber, R. 2014, Flexibility, muscle strength and running biomechanical adaptations in older runners, Clinical Biomechanics, No.29, Vol. 3, pp.304–310.
Matheson, G., Macintyre, J., Taunton, J. et al. 1989, Musculoskeletal injuries associated with physical activity in older adults, Medicine and Science in Sport and Exercise, Vol. 21, pp. 379-385.
Stenroth et al., 2012
Jimenez-Garcia, J., Hita-Contreras, F., de la Torre-Cruz, M., Fabrega-Cuadros, R., Alibar-Almazan, A., Cruz-Diaz, D. et al. 2019, Risk of Falls in Healthy Older Adults: benefits of high-intensity interval training using lower body suspension exercises, Journal of Aging and Physical Activity, Vol. 27, pp. 325-333.
Korhonen MT, Mero AA, Alen M, et al. 2009, Biomechanical and skeletal muscle determinants of maximum running speed with aging. Med Sci Sports Exerc., Vol. 41, No. 4. pp. 844–56.
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