When we are faced with difficult or inconvenient situations, we tend to question ourselves on if we can or can't do something. I just went through this thought process when they announced the jeans challenge. Even though overall my leg is better, I still have to make sure I don't overdo it and make it worse. Because taking on this challenge means adding another small group PACK session to my schedule, and having challenging goals to meet, I questioned on if I would be able to do the challenge and still get something out of it. But, I shouldn't have questioned on if I could do it, just will I face it, because the trainers can always modify any exercise if needed and I can still be successful.
Don't make it a question on if you can do something, because I'm pretty sure you would be able to do whatever you're facing. It's just up to you to make it happen. Make it a question of "What will I do to make sure I succeed?".