Strength Training
Diary — Why
Bowling in the
Dark Never Works
Mark McCormack's bowling experiment — and what it reveals about training without keeping score
There is a well-known ELO song from the 1970s about a shy, hesitant man who overcomes his own inertia and discovers what he is capable of when he finally commits to action. It is a useful metaphor for the trainee who suspects that a training diary might help but has never quite got around to starting one.
The case for keeping one is made most directly by a story from a very different world — corporate management, a bowling alley, and an executive with a curtain.
Bowling in the dark —
the most direct demonstration of why feedback matters.
Mark McCormack founded the modern sports management industry, representing athletes including Bjorn Borg, Sebastian Coe, and Jack Nicklaus at the peak of their careers. In his book The 110% Solution, he describes a management experiment designed to make a single point about feedback as vividly as possible.
An executive, a bowling alley, and a curtain.
An executive, looking for ways to drive home to his employees the value of feedback, took them bowling. For a while they bowled normally and the usual competitive dynamics developed — everyone wanted to win. Then later in the evening, the executive had a curtain drawn across the lanes which allowed the ball to roll through but blocked the view of the pins.
Suddenly the employees were bowling blind and could no longer keep score. The result? Teamwork fell apart and the employees grew annoyed and frustrated. The executive apologised — but he had made his point. Being unable to keep score and measure your results is the equivalent of bowling in the dark.
The moment the curtain went up, motivation collapsed. Not because the bowling had become harder — the physical action was identical. Because the feedback had disappeared. Without it, effort feels purposeless. With it, even modest progress feels like progress.
The connection to training is direct. The trainee who does not record their sessions is bowling with a curtain across the lanes. They are expending genuine effort — but without the feedback that tells them whether that effort is producing anything, or what to adjust when it stops. The diary is what takes the curtain down.
Progressive overload — the operating principle of the Minimum Effective Strength System — is only measurable with a record. Without documentation, the system is a principle without a practice. With it, every session has a specific target and every result is a data point.
Four things a training diary does
that memory and intention cannot.
Each one addresses a specific failure mode that training without records produces.
- It makes progress visible — the accumulated record of small gains over weeks and months is motivating in a way that individual sessions are not. Progress is rarely dramatic in any single session and is frequently invisible without the longer view a diary provides.
- It identifies what is working — scanning back through recorded sessions to find the periods of fastest progress reveals the specific conditions — rest, loading, frequency — that produced the best results. Without the record, these conditions cannot be identified or repeated.
- It provides early warning of stagnation — a training diary makes it impossible to accidentally repeat the same weights for the same repetitions for months without noticing. The record makes stagnation visible within sessions, not retrospectively after months of wasted effort.
- It creates accountability — the specific target written down at the end of the previous session creates a commitment to the next session that a general intention does not. For the research on how this accountability mechanism works, see the boost workout results page — Dr Gail Matthews's 267-volunteer study showed a 76.7% improvement in goal achievement from writing goals down and reporting progress.
Starting a strength training diary —
the format that works.
The format is less important than the consistency. A small notebook kept in the kit bag, a notes app on a smartphone, a spreadsheet — any of these works. The one that will be used consistently is the right choice.
Start with these four. Add the others when the habit is established.
- Weights and repetitions for each working set The foundation. Everything else builds on this.
- Target for next session Written immediately after the final set — one more repetition or a small weight increase. This is the specific number that motivates the next session.
- Bodyweight — weekly Not daily — the day-to-day variation is noise. Weekly provides the trend.
- How the session felt One line — energy level, any unusual soreness or fatigue entering the session. The early warning signal for overtraining before it becomes an injury.
- Tape measurements — monthly Arms, chest, waist. Monthly measurements reveal body composition changes that bodyweight alone does not show — muscle gain alongside fat loss produces a stable scale weight and improving measurements simultaneously.
The complete strategy for how to use the training diary as a session planning tool — including Mike Mentzer's Heavy Duty three-step night-before preparation approach — is covered on the workout training log page.
Take the curtain down. Record every session. Review before the next. The diary is not the training — it is what makes the training productive rather than merely strenuous. The Minimum Effective Strength System treats session documentation as a non-negotiable element of the framework — because effort without feedback is bowling in the dark.