Are you feeling stiffer?
It's not your imagination. Your joints have been stiffening as you age. But not just since becoming an adult, your joint mobility has reduced almost exponentially since early childhood (Harjodh et al., 2017).
Figure 1 indicates how joint mobility changes as we age using the Beighton scale (see Figure 2).
Average Beighton scores across the Lifespan
Measuring Joint Hypermobility
Why are we more flexible when we are younger?
Our skeletal system is still developing.
We are born with around 300 bones that fuse over time to form 208 for most adults. Our skeletons start with large proportions of cartilage that develop into bone as we age. This provides our skeletons with the malleability to get through the birth canal. The bones of our joints also have greater freedom of movement. We are born with shallow hip joints that deepen and become congruent with the head of the femur (ball of the ball and socket joint) as we age (Loh & Woollett, 2021). This is why babies have such mobile hips. Our body proportions are also very different, meaning it's much easier for a baby to touch its toes, for example, than an adult.
Greater hydration = greater tissue extensibility.
As babies, we are around 70-80% water. This percentage reduces as we age to about 60% for adult males and 50% for adult females. It may reduce even further in older adults. Hydration is essential for the mobility of our joints and the extensibility of our tissues. A more significant percentage of water in muscles and connective tissue such as tendons, ligaments, fascia and cartilage is another reason children are more mobile than adults.
Why do we get stiffer as we age?
As we age, we become less active. On average older adults (65+) spend more time sitting (over 6 hours a day) compared to adults under 65 (approx 4.5 hours). Older adults also spend less time each day being physically active and are less likely to meet physical activity guidelines (AIHW, 2018). While WHO guidelines do not include any recommendations for flexibility training, it is safe to assume people are less likely to stretch or participate in activities that require flexibility as they age if they are generally less active and more sedentary.
Increased incidents of chronic health conditions
Chronic health conditions have a negative impact on flexibility. How depends on the condition, but it's common for chronic conditions to increase pain and limit a person's ability to be physically active. 50% of Australians have at least one of the following chronic health conditions: arthritis, asthma, back pain, cancer, cardiovascular disease, diabetes and mental health conditions (AIHW, 2020). The incidence of chronic health conditions increases as we age, contributing to decreases in joint range over the lifespan.
But this isn't the whole picture
Many adults I work with report they are more flexible now than when they were younger.
Flexibility isn't just joint range and tissue extensibility. In part, flexibility is the expression of our ability to access the mobility available to us. This involves motor planning, coordination, strength, control, nervous system regulation, self-awareness and cognition.
Flexibility improves when it is trained
Flexibility training and stretching programs have consistently shown to increase joint range in all age groups, including older adults (Donti et al., 2022; La Greca et al., 2022; Stathokosta et al., 2012). The training type and volume don't make a difference, except in children who respond better to high-volume programming (Donti et al., 2022).
Despite physiological changes that reduce joint range and tissue extensibility, we can improve flexibility as we age.
What improves as we age?
Pain tolerance & emotional regulation
Pain is a normal and expected part of flexibility training. Flexibility training predominantly involves habitation to reduce pain sensitivity and increase tolerance. Emotional regulation strategies, including pain acceptance, mindfulness and distraction, are essential for reducing pain perception (Haspert et al., 2020). Children have difficulty regulating emotions and are less capable of employing strategies to minimise pain and distress as their brains are still developing. As such, they are less tolerant of pain and have more difficulty sitting with the discomfort of a stretch than adults. Children respond best to active distraction techniques that require engagement over passive distractions and other cognitive/emotional strategies (Elsayed et al., 2020).
Strength peaks for both sexes between 30-39 years of age but is relatively well maintained until after 60 (Massy-Westropp et al., 2011). Just like flexibility, strength improves in all age groups with strength training. Increased muscle mass and strength are associated with increased flexibility in over 50's (Gao et al., 2023). Muscle strength improves joint stability, balance and control, reducing injury risk and supporting flexibility.
Self-perception of one's body, including proprioception (joint position sense), interoception (awareness of internal sensations) and multisensory perception (integration of signals from multiple senses), takes a long time to develop. Young children have difficulty detecting and understanding their bodily cues. Older adults have better self-perception speed and accuracy than young adults (Ferracci & Brancucci, 2019). Good self-perception is beneficial for flexibility training.
Australian Institute of Health and Welfare. (2018). Physical activity across the life stages. Canberra: AIHW. https://www.aihw.gov.au/reports/physical-activity/physical-activity-across-the-life-stages/contents/table-of-contents
Elsayed, Z., Rahma, S., & Bahgat, S. (2020). Effect of Active versus Passive Distraction Technique on Controlling Pain Associated with Invasive Nursing Procedures among School Aged Children (Doctoral dissertation, Tanta University). DOI:10.9790/1959-0706037081
Ferracci, S., & Brancucci, A. (2019). The influence of age on the rubber hand illusion. Consciousness and Cognition, 73, 102756. https://doi.org/10.1016/j.concog.2019.05.004
Gao, P., Gan, D., Li, S., Kang, Q., Wang, X., Zheng, W., Xu, X., Zhao, X., He, W., Wu, J., Lu, Y., Hsing, A. W., & Zhu, S. (2023). Cross-sectional and longitudinal associations between body flexibility and sarcopenia. Journal of Cachexia, Sarcopenia and Muscle, 14(1), 534-544. https://doi.org/10.1002/jcsm.13157
Harjodh Singh et.al., Beighton scores and cut-offs across the lifespan: cross-sectional study of an Australian population, Rheumatology, Volume 56, Issue 11, November 2017, Pages 1857–1864, https://doi.org/10.1093/rheumatology/kex043
Haspert, V., Wieser, M. J., Pauli, P., & Reicherts, P. (2020). Acceptance-Based Emotion Regulation Reduces Subjective and Physiological Pain Responses. Frontiers in Psychology, 11, 535033. https://doi.org/10.3389/fpsyg.2020.01514
La Greca S, Rapali M, Ciaprini G, Russo L, Vinciguerra MG, Di Giminiani R. Acute and Chronic Effects of Supervised Flexibility Training in Older Adults: A Comparison of Two Different Conditioning Programs. International Journal of Environmental Research and Public Health. 2022; 19(24):16974. https://doi.org/10.3390/ijerph192416974
Massy-Westropp NM, Gill TK, Taylor AW, Bohannon RW, Hill CL. Hand Grip Strength: age and gender stratified normative data in a population-based study. BMC Res Notes. 2011 Apr 14;4:127. https://doi.org/10.1186/1756-0500-4-127
Stathokostas, L., Little, R., Vandervoort, A. A., & Paterson, D. H. (2012). Flexibility training and functional ability in older adults: a systematic review. Journal of aging research, 2012.https://doi.org/10.1155/2012/306818