You often get aches at the start — practising this? (4)
I believe the answer is:
yoga
'practising this?' is the definition.
The definition suggests a singular noun which matches the answer.
'you often get aches at the start' is the wordplay.
'at the start' suggests taking the first letters.
The first letters of 'you often get aches' is 'YOGA'.
Can you help me to learn more?
(Other definitions for yoga that I've seen before include "Hindu ascetic system" , "Hindu system of exercise and meditation" , "Relaxing Hindu spiritual discipline" , "Hindu philosophical system" , "Hindu postural discipline" .)