greyhound looks a bit quad dominant...
were you kidding?
greyhound has big hamstrings on the hindlimbs, check it:
2003: Functional trade-offs in the limb muscles of dogs selected for running vs. fighting
The physical demands of rapid and economical running differ from those of physical fighting such that functional trade-offs may prevent simultaneous evolution of optimal performance in both behaviours. Here we test three hypotheses of functional trade-off by measuring determinants of limb musculoskeletal function in two breeds of domestic dogs that have undergone intense artificial selection for running (Greyhound) or fighting performance (Pit Bull).
We found that Greyhounds differ from Pit Bulls in having relatively less muscle mass distally in their limbs, weaker muscles in their forelimbs than their hindlimbs, and a much greater capacity for elastic storage in the in-series tendons of the extensor muscles of their ankle joints. These observations are consistent with the hypothesis that specialization for rapid or economical running can limit fighting performance and vice versa. We suggest that functional trade-offs that prevent simultaneous evolution of optimal performance in both locomotor and fighting abilities are widespread taxonomically.
so, they have "less muscle distally", ie, the muscle belly is higher towards the origin of the bone, which means they have longer tendons, especially in their lower leg (ankles, ankle extensors specifically).
very similar to humans and elite sprinting.
peace