I think it can do both. It's important to realize that since gender is a social construct, activities and qualities are coded masculine and feminine rather than being inherently one or the other. So competitiveness is no more inherently related to males than empathy is to females--and studies show than men and women are in fact equally empathetic.
Sports, like most things, can cut both ways. We in the west often associate strength, sweat, competition, toughness, stamina and vigorous physical exertion with masculinity. Allowing women to these qualities definitely expands our understanding of gender and weakens the binary. On the other hand, when we say that the only way to be successful at anything is to do it in the masculine way, we reinforce the binary. For example many coaches have found that girls thrive under different coaching techniques than boys do, likely because of the way boys and girls are socialized differently. So if even within a given sport if we praise and prioritize 'masculine' ways of doing and achieving (even when these masculine forms are expressed by women) then we reinforce the binary.
For example, think of the way we think of women's hockey vs regular men's "real" hockey. Should women be allowed to get out the skates and whoop it up? Most of us would say sure. But is women's hockey "real" hockey if it doesn't include checking? Is it inherently boring and inferior if it's not as intentional about hurting people? Is it the soft lady kind, or does it emphasize a different skill set? Would women players prefer to check if they could, and what would that mean to them? How do male players feel about the violence encoded in the sport? If little boys have to be trained to be aggressive on the ice (and they do) and if adult men have to suppress their own fear of violence on the ice (and they do) then is how the aggression of the sport more appropriate to men than women? You can see the fluidity here. Gender expression, coding and policing shift all the time. That's why within academics gender expression is commonly referred to as a "performance": because we have a script but we're always revising and improvising.
It's not worth getting off topic for though.
