A study 1 in the journal of Ergonomics investigated the likelihood of variability of height loss in the sitting position being impacted by the time of day. The day-to-day variability in asymptomatic participants was also analyzed. The results shared data about height loss changes in the morning and the afternoon.
LBP and Height Loss
Millions of people (ranging from the young to the elderly) suffer from low back pain, or LBP, around the world. Such a condition has physical, psychological, and social implications. Sedentary work (which involves sitting for long periods) has become quite common for students, office workers, and more. Prolonged sitting increases the risk of lumbar disc pathology (which is, in part, associated with loading on the lumbar discs).
Spinal loading is considered as a cause for LBP as it causes spinal tissue shrinkage. Such shrinkage is known as height loss. Studies do show that prolonged sitting can lead to height shrinkage and thus, LBP.
Effects of Time of Day in Height Loss
Certain studies display a significant difference between height loss following loading activity applied during the morning and in the afternoon. Changes in height seem to occur in a ‘fast’ and ‘slow’ phase. The rate of change is higher when individuals wake up in the morning, and then it slows down throughout the day. That’s why, for ergonomic researchers, the influence of time of day is essential to consider when it comes to height loss. Day-to-day variability of height loss response is another factor to observe the influence of activities done during the day.
The Study
The research utilized a test-retest design to assess the effects of time of day on the variability of height loss. A total of fifty asymptomatic participants (25 males and 25 females) were involved. The study only included participants without current neck or back pain.
Take note, the participants were requested to sleep for eight hours (before every test) as well as to avoid vigorous activity for 24 hours before every test.
A seated stadiometer device was used for measuring height loss response.
What was found?
The current study is deemed to be the first of its kind to investigate the effects of time of day on the height loss response variability because of sitting for two consecutive days.
No significant difference in the magnitude of height loss during the morning and the afternoon was observed. Take note, changes higher than 0.886 mm (morning) and 1.128 mm (afternoon) can be attributed to intervention effects.
The study suggested the collection of future data during the morning or in the afternoon. Also, more significant responses are needed to confidently state that height loss responses have been influenced by an intervention.
