Yes. By stretching and compressing lots of tendon, ligaments and cartilages in the wrist and other tennis tissues. No firing of those snap muscles though, no matter what they are.
Recent research indicated that for the long muscles the tendons did not play as important as part in stretching as had earlier been thought. The Titin in each sarcomere probably contributes most force despite what text books had been saying for decades about tendons. This is one reason why Titin research is important. Unfortunately, the new text books may not have caught up yet but don't believe it when they say the tendons are the source of muscle stretched force - it's the Titin!
I am trying to take the approach of the researchers, Marshall, Elliott et al, that examined the joint motions that contributed to the serve, forehand and maybe also other strokes. They measured the most significat joint motions and the distance from their axis of rotation to impact. Each joint motion was then assigned a 'contribution' to racket head speed at any instant including impact. Search:
Biomechanics and Tennis, Elliott They also measured the forehand, but that forehand technique of 20 years ago, compared to Dimitrov's today, may have changed. ?
I looked up the table in Biomechanics and Tennis.
Forehand in red. 20% of forward racket head speed at impact from wrist flexion and radial deviation. Correction - on looking at the video again 20% seems reasonable for Dimitrov wrist flexion.
Table 2 Approximate contributions to impact racquet velocity (%)
Power serve Topspin forehand (forward direction)
Shoulder 10
15
Upper arm
Horizontal flexion 15
25
Internal rotation 40
40
Forearm
Extension Negligible
Negligible
Pronation 5
Negligible
Hand
Flexion (palm/ulnar) 30 –
Flexion (palmar/radial) –
20
Correction - Looking at the video again there is enough flexion to be considerable. Maximum wrist extension to less extension, that's wrist flexion*, at impact on second viewing seems considerable for racket head speed in comparison to the contributions of the body turn and shoulder joint swing.
Look at Dimitrov's maximum wrist extension and then his extension at impact - that is, wrist flexion*. The distance from the turning body and shoulder to impact is considerably longer than the wrist to racket impact spot meaning higher racket head speed from the body turn and shoulder.
Look at the Essential Tennis video and look at each joint and estimate the racket head speed being produced by each joint motion. Think of each joint motion by itself.
* [There is a confusing issue in describing joint motions - both location and motion use the same terms -
1) Anatomical Terms of Joint Location - describe joint angle with reference to a defined zero. Example, 'The wrist is at an angle of extension of 15 d.'
2) Anatomical Terms of Joint Motion - describes the direction of joint travel toward the maximum joint angle of for example, flexion or extension.
Example, 'The wrist is flexing' - meaning moving toward the angle of maximum flexion.]