It's your character, so fair enough, from what I know of First Nation People's they tended to favour guerilla tactics where being physically robust in a pushing and shoving sort of way (which most medieval battles tended to come down to on the front line) was not a major concern, nor something they trained for. Though there's always anomalies in every population, I'm sure some favoured physical strength over speed and agility in combat, though the tomahawk at least to me feels like an agile weapon that wouldn't necessarily be of more use in the hands of someone stronger. That's the only reason I made the assumption of him having a sort of wiry strength (That and you mentioned he didn't seem overly muscular.)

Then again, though I can't remember if it was explicitly stated looking at your character's weapons he seems to be from a modern setting, so I suppose what was historically true is irrelevant. 

A good baseline for strength and speed is to decide what trait you'd like your character to favour and find what the world record in terms of Olympic sport is, then scale down somewhat for realism. That's how I personally set my character stats anywho. Stronger characters -tend- to be less agile, though that doesn't have to translate to being slower in a straight sprint. Height and build have similar advantages and disadvantages. 

At the very least, a strong character will be able to lift their own body weight. Obviously in combat factors like height and reach can be just as important to the strength of someone's muscles, but at some point the direct statistical strength of your character may come into question, as contests of strength are somewhat common. Speed is similarly important, if you want to outrun someone or something.