Best fitness challenge app for coaches

There are roughly 40-60 apps claiming to support fitness coaches, but most are either generic workout-logging platforms (MyFitnessPal, Strong) or high-friction SaaS tools built for corporate wellness (Fittr, Trainerize). The actual pain points coaches face are threefold: apps don't let them set custom challenge rules and scoring systems, most lack built-in community engagement features that make challenges *social*, and pricing models punish coaches with 20+ clients. The gap isn't in tracking or programming—it's in the *engagement layer*. A coach needs an app that makes running 8-week challenges, managing team leaderboards, issuing real-time feedback, and collecting proof-of-work (video submissions, photos) frictionless. Most existing solutions require coaches to juggle Slack, Google Sheets, and whatever app they're using. The real opportunity is a dedicated platform that treats the *challenge structure itself* as the product, not just a feature bolted onto a fitness app. New shippers should focus on: (1) white-label or deeply customizable challenge templates coaches can launch in <5 minutes, (2) native integrations with Wearables (Apple Watch, Oura Ring) to eliminate manual logging, and (3) a coach-to-coach marketplace where top-performing challenge designs can be shared and monetized.