human figure practice

Okay, from left to right, I suppose. The head on the female seems like it's lacking a jawbone. While it's typical to simplify the head shape in a gesture drawing, the way it seems to be drawn looks like those pointy no-chin animu characters. It is perhaps a little unnerving that the trapezius muscles seem to be missing as well- you've got them on the male figure. The collarbones seems set a little high, but that may be linked to the issue with the lack of trapezius muscles. The neck seems a bit long as well.

I'm not sure if this is just personal preference, stylistic inclination, or the fact that I'm fairly broad shouldered myself in real life, but I think the shoulders on the female need to be a bit wider and a little more squared off. The breasts seem unrealistic- they're too bowling-ball-glued-to-chest-like. If a female has larger (even medium-sized) breasts, they sag downwards (maybe like a cartoony water drop shape) without the support of a bra. The figure itself seems to be exaggerated- I'm not sure if you're going for a cartoony style here or something, but the stomach looks like it's horribly cinched by an invisible corset. I don't think even anorexic models look quite like that. Her hands look really tiny, and I'm not really sure what it is with the arms that makes them look disjointed.

The lower half of the female's body kind of bothers me. The pose looks really forced, as if she is turning her right leg and left foot inward very awkwardly. Maybe something that would help make the pose more natural would be indicating the hips turned at an angle? Putting in some foreshortening may help as well, the right leg looks broken for some reason, and if stretched out, may be a little bit longer than the left leg. I think the ankle area could benefit from adding that knobby bone on the outside of the ankle (though I forget what it's called, and maybe that's just a style nitpick), and indicating the knee joints with more detail would be nice.

The male figure clearly has some stylistic liberties taken with it. That being said, the neck seems to be just a little short; it'd probably be remedied by scaling back the trapezius muscles a little and drawing the neck in a bit more in that space. Now, I'll be honest here, I'm not all that well-versed in muscular figures (all the males I ever had to draw in my classes were pretty much skin-and-bone). A male with this figure (especially if you're looking into stylizing for cartoons) would also benefit from a more substantial jawline, to look more "manlier".

I feel as if he's lacking a fold of skin/some possible muscle just above where the pelvis/hipbone would sit. I'm assuming this kind of figure is what you're going for, with a more exaggerated style? Said muscle/fold of skin in that linked picture would be the two diagonal lines just above the guy's belt.

The legs seem a little plain, especially if we're assuming the male figure is one to work out a lot. I'd try to define some of the muscle groups more, like the hamstrings/quads so that the legs don't seem like ten-year-old tree trunks. I'd also probably push the calves just a little bit more for good measure as well.

Personally, I find the poses kind of bleh at best; like the other person said, they are a bit unbalanced. In the future, maybe you can draw in a logical support for a bent leg like that, like a chair or something.