+5%
More participation at comparable races
RunSignup’s same-race comparison controls for its platform’s expansion. It describes races in that sample, not every U.S. event.
RunSignup’s 2025 report ↗The thinking behind Split
A bigger field.
A shared goal.
Participation is growing in hybrid racing and parts of running. We’re studying what that means for the people doing the training.
The numbers.
The context.
These are separate signals of participation and demand. They measure different things, and cannot be added together to estimate Split’s market.
Two seasons of reported participation
Season totals reported by commercial partners.
Bars show reported lower bounds. Totals may include repeat entrants; growth also reflects more events. This is not a count of potential paying customers.
+18%
Demand for a place on the start line
1,338,544 applications for the 2027 race, versus 1,133,813 for 2026. Applications were made in 2026, from the UK and overseas. They are not race entries or finishers.
London Marathon Events ↗Understand the week.
Not just the race.
Participation tells us where to look. Conversations and real use tell us what to build.
Audience hypotheses to validateThe endurance athlete adding strength
“I know aerobic training. Some of these strength movements are new.”
- Need to test
- Strength foundations and station guidance that respect current experience.
- What we’ll ask
- Which movements need explanation? If your sport is cycling or swimming, how much running do you comfortably do?
The lifter adding endurance
“I want to build running into the lifting routine I enjoy.”
- Need to test
- A manageable running starting point alongside familiar strength work.
- What we’ll ask
- Which sessions clash, and what do you change when your legs are tired?
The athlete already doing both
“I train strength and endurance. Help me bring them together for this event.”
- Need to test
- Useful station and transition practice for Singles or Doubles.
- What we’ll ask
- What does your current mixed week miss, and what changes when you prepare with a partner?
The person building a routine
“Give me a starting point that doesn’t assume I already train.”
- Need to test
- Shorter run/walk sessions, basic movements and clear explanations.
- What we’ll ask
- What feels approachable, what is confusing, and what helps you return next week?
Illustrative needs, not customer testimonials or survey results. These starting hypotheses come from the problem that led us to build Split.
Good alternatives.
A focused opportunity.
We reviewed competitors’ own documentation. This is a comparison of described capabilities, not a hands-on performance ranking. Features can change.
7 alternatives
ROXFITHybrid training & race tools
Workouts, HYPE AI creation, Health connectivity and a weekly planner. Ultra advertises partner-specific doubles pacing.
FAQ ↗ Ultra ↗Its FAQ says structured multiweek plans aren’t yet available. Split already prescribes a multiweek schedule; imports and doubles tools alone aren’t unique.
CentrCoached hybrid programs
HYROX-certified 12-week programs mixing strength, cardio and race practice, with equipment alternatives.
Program details ↗Beginner hybrid plans and substitutions already exist. Split must earn its place through a useful fit with someone’s actual training week.
RunnaRunning plans with strength
Race-running plans, optional strength and scheduling flexibility. Its strength FAQ says strength sessions don’t influence adaptive running recommendations.
Strength FAQ ↗Considering lifting and running together is a future opportunity for Split. We have not yet built that comprehensive adjustment system.
AthleticaAdaptive multisport coaching
Adaptive plans across endurance sports and HYROX, with contextual conversational coaching.
Official FAQ ↗AI coaching and support for more sports are already competitive features. Split needs to solve a specific problem well, not just add a chat box.
TrainingPeaksPlanning & detailed analysis
Training plans, fitness and fatigue analysis, coach communication, strength programming and Apple Watch integration.
Premium ↗ Strength ↗ Apple Watch ↗A focused first-race experience is a proposition to test. Split does not currently match its analytical depth.
Strava / Apple FitnessActivity & shared motivation
Workout visibility, activity totals and shared motivation. Strava’s Health import excludes third-party-written workouts; separate direct integrations may exist.
Strava Health ↗ Apple sharing ↗Split accepts compatible third-party Health records. Partner preparation could go beyond a feed, but we need to validate that need and deliver it.
AthlinksRace results & social history
Claimed results, personal records, race history, likes and comments. Athlinks is also available within the Life Time app.
Race history guide ↗ Life Time integration ↗Race profiles are a useful idea, not an exclusive one. Split could connect the preparation, teammates, result and next goal into a continuous shared story.
Why try the current prototype?
A starting point that reflects your background. Endurance, weightlifting, both or starting out shape the emphasis of template-based starter sessions. Current running ability is assessed separately.
Your race format. Open Singles and Open Doubles preparation, format-specific station guidance, and a completion goal or optional personal time target.
Your actual training. Compatible Apple Health imports, indoor and outdoor runs, plus a separate all-workout history and active calories.
Room for life. Move sessions, change usual days and manually complete an adapted workout with its actual time.
A shared goal. Private partner progress summaries are implemented and still being tested, with a focus on preparing together.
See the real prototype ↗Useful combinations, not proven superiority. Split uses starter templates and explicit profile-based rules, not AI coaching or comprehensive fatigue or injury adaptation. Its limited effort-based running adjustment is not a whole-training-load system. Two-account sharing still needs complete device testing. Health imports depend on permissions and usable records.
Build around
the next decision.
The research points to three priorities. These are proposed improvements, not features available today.
Future exploration / no promised release dates- 01First: trust
Make every workout understandable.
Explain why a recorded workout did or didn’t match. Explore linking relevant records, partial completion and clear manual overrides, without double-counting time or calories.
- 02Next: useful adjustments
Respond to the whole training week.
Consider strength and endurance together. Use short effort and fatigue check-ins, explain suggested changes, and let the athlete accept or undo them. Start with coach-reviewed rules. AI coaching and broader load adaptation remain future exploration, alongside support for other race types.
- 03Then: coordination
Prepare as two people, for one race.
Explore individual plans with shared availability, joint sessions and coordinated changes. A shared goal shouldn’t require identical training. Friend groups could extend this beyond a single race partner.
Future concept / not an app screenshot
Your training has a story.
We’re exploring profiles that connect the races you’ve participated in or completed, the people you trained with, and the goal you’re working toward next.
Possible details: event, date, format, participation or completion status, optional result, teammate and a personal reflection. Self-reported achievements would be distinguished from official-linked results. Sharing would be opt-in.
- PrepareFollow the work
Training progress with your partner or friends.
- ParticipateKeep the memory
Events, results and the people beside you.
- Go againShare the next goal
Carry your history into a new challenge.
Current status: one-partner sharing is implemented and still being tested. Friend groups, race-history profiles and result verification are future concepts.
Social race records already exist in Athlinks, and Strava connects race discovery with training. Our opportunity to test is how well Split brings the everyday preparation and shared race story together.
We still need to earn the answer.
Our proposed first study: 5–10 participants across endurance, weightlifting, both and starting out, including Open Singles entrants and Doubles pairs, using a reliable beta for several weeks. This small exploratory sample will not establish differences between groups. We’ll assess setup clarity, whether instructions fit current experience, workout-import success, repeated use, coordination effort and willingness to pay after using it. Participation growth alone doesn’t establish demand for Split.
Sources, scope & limitations
Reviewed 11 November 2026. Participation figures come from the linked event organisations, partners and platforms; we did not independently audit their datasets. Each figure keeps its own period, population and unit. Repeat entries, selective platforms, event capacity and changing coverage limit comparisons.
The HYROX bars use reported lower bounds from two different partners. RunSignup measures comparable races. London measures ballot applications. USA Triathlon measures ranked-event participation. None is a standalone estimate of unique customers, revenue or willingness to subscribe.
Competitor descriptions come from official product and support pages, not hands-on benchmarking. Split descriptions were checked against the current prototype. Audience profiles and proposed features are hypotheses, and no claim of exclusivity or improved race results is made.
Different starting points.
Your own sp/it.
Four backgrounds. Singles or Doubles. A starter plan you can inspect in the current prototype.
Walk through Split