More Hard Workouts, Faster Marathon? Read the Boston Data Carefully

One more hard workout each week, 16 minutes faster at the marathon. That is an appealing reading of a study of Boston Marathon runners. It is also a poor way to choose next Tuesday’s session.

The study in Sports Medicine analyzed 917 finishers of the 2022 Boston Marathon. Researchers surveyed training across the year before the race and matched responses with official finish times. In the period 12 to 4 months before Boston, each additional weekly “quality” session was associated with a finish time about 16.2 minutes faster in their statistical model. In the final four months, the corresponding estimate was about 17 minutes.

Those are differences between runners in a survey, not minutes a runner can expect to gain by adding intervals. The study did not assign workouts, test a training intervention, or measure what happened when a particular runner added a session.

Who was in the study?

This was a Boston field, not a random sample of first-time marathoners. The 495 women reported an average of about 40 miles per week; the 422 men averaged about 42 miles. Average finish times were 3:53 and 3:35, respectively. The researchers described most participants as trained or developmental, non-elite runners.

That context matters. A runner with a durable year of training may be able to handle a workload that a new marathoner cannot. It also means that faster runners may simply be able to sustain more running and more demanding sessions. The models accounted for age, sex, and reported running experience, but they could not remove every difference in fitness, injury history, fueling, or recovery.

The survey counted quality sessions; it did not capture their precise pace, duration, or intensity distribution. It cannot tell you that a particular interval set is better than a tempo run, or that moving from one hard day to two is safe for your present schedule. For ways to define the work itself, see our lactate-threshold guide and short-interval discussion.

The quieter result: more work and some reduction both appeared

Higher overall running exposure was also associated with faster finishes. The result is not an argument to replace easy mileage with hard sessions. In the study’s earlier training period, an additional weekly run was associated with a roughly 3.6-minute faster finish, and greater weekly distance was associated with faster times. These are model estimates, not additive credits you can collect on a training plan.

Runners who reported fewer weekly running sessions in the final four months than in the preceding eight months finished about three minutes faster on average than those who maintained or increased frequency, after the study’s adjustments. Yet, within that final four-month period, runners doing more running also tended to be faster. Both findings can coexist: a runner’s long-term training base and the change relative to that base are different comparisons.

Do not read the three-minute result as an instruction to cut a day exactly four months before race day. That window includes race-specific training and the final taper. The researchers could not distinguish their separate effects. They also could not identify whether a reduced running schedule reflected deliberate planning, a busy life, or an injury. Cross-training in that period was associated with faster times, but the survey could not separate cycling, strength work, and other activities well enough to prescribe one of them.

What to do with your own training week

Editorial planning advice: Keep a repeatable base before chasing another hard day. Look at the last several weeks of total miles, long runs, hard sessions, and how you felt afterward. If a quality workout leaves the next easy runs unusually difficult, make that session sustainable before adding another. If you decide to experiment, replace an existing workout or reduce another demand and reassess over several weeks. This is a way to observe your response, not a protocol tested by the Boston study.

Our marathon long-run guide explains why one workout cannot stand in for the weekly pattern. If time away from running has broken that pattern, use the return-after-a-break guide before adding intensity.

The useful finding is narrower than the headline: in this experienced group, faster finishes traveled with substantial training, quality sessions, and a relative reduction in run frequency later in the year. The study cannot promise a 16-minute improvement, set your ideal number of hard days, or prove that fewer runs caused faster racing.

Sources

• DeJong Lempke and colleagues, “Training Volume and Training Frequency Changes Associated with Boston Marathon Race Performance,” Sports Medicine. Original open-access survey and regression analysis of 917 runners; source for all study figures and limitations above.