A new joint research brief from Strava and the AI coaching app Runna, released on Monday, has put a number on something that experienced marathoners have long asserted instinctively: training in a group makes the back half of a marathon easier. Looking at anonymised activity data from a sample of more than 1.4 million Strava users who completed a marathon in 2025, the brief reports that athletes who logged at least one structured club session per week were 16% less likely to experience a "positive split" of more than five minutes — the standard quantitative proxy for hitting the wall.
The headline number sits inside a wider set of findings about how amateur marathoners are training in 2026. Active club membership on Strava nearly quadrupled in 2025, with running clubs growing 3.5 times by member count, and the platform now hosts roughly one million clubs in total. Friday remains the least popular day on which to log a workout — the most common rest day among Runna users following a four-runs-per-week marathon plan — and strength work has continued its rise into mainstream marathon prep, used by 40% of women in the dataset compared with 27% of men. Median weekly volume on Runna's marathon plans has crept up to 30 miles for the under-35 cohort, with peak weeks averaging 41 miles.
The most striking demographic finding is the generational split in recovery. Runners over 50 averaged 10.4 days between their marathon and their next logged run, while Gen Z athletes — defined as those under 28 — were back outside in a median of 5.2 days. Strava's research lead Hannah Borenstein cautioned that the difference is partly behavioural rather than physiological, but that the gap had widened from 4.1 days to 5.2 days in a single twelve-month window, raising injury-risk questions the company is monitoring with a follow-on study expected in the autumn.
For coaches, the more actionable findings sit in the social training data. The 16% wall-protection figure for club runners is double the comparable benefit estimate from Runna's similar 2024 internal report, and rises to 23% for runners who logged a long run inside a club at least three times during their training block. Runna's head of coaching Ben Parker noted that the figure does not control for genetic or socio-economic factors, but argued that the consistency afforded by a regular group long run "is probably the single highest-leverage intervention an amateur marathoner can make on their own training". The brief also reports that club runners were 15% more likely to hit a specific stated time goal — a far higher number than any nutrition or footwear intervention measured in the same dataset.
The research lands at an opportune moment for both companies, with Strava reporting a 22% year-on-year surge in marathon training plan downloads in the seven days before Sunday's London Marathon and Runna confirming that its UK active-user base passed one million for the first time in March. Both companies are due to expand the analysis later in the year with a longitudinal study tracking a subset of London 2026 finishers from race day through their next training block. For now, the headline takeaway is unambiguous: if you want to fade less in the closing miles, the cheapest known intervention is to find a Tuesday night that already has a group on it.