# Study 000A Abstract

## Title

Six-Year Longitudinal Adaptation Under Altered Biomechanics: Workload, Performance, And Conserved Mechanics In A Nonstandard Movement System

## Abstract

This single-subject flagship synthesis study evaluated a broader six-year question than the earlier foundation studies: what changed, what remained comparatively anchored, and what adaptation pathway the data support in the setting of altered biomechanics and a nonstandard movement system. The study was built from the Stage 5 Garmin main package and packaged source tables covering annual ecology, daily master timeline context, late-window food overlap, and QC-pass high-resolution running mechanics.

The six-year record showed large ecological change, not just faster running. Structured training shifted from heavily running-dominant in 2020, through indoor-conditioning-heavy years, to a strongly running-dominant profile again in 2026. The strongest restructuring occurred in `Indoor Pivot And High-Resolution Adaptation`, where indoor share averaged `64.7%`. In the high-resolution mechanics window, adaptation was substantial. Comparing the first and last 30 QC-pass sessions, pace changed by `-29.99%`, cadence by `21.15%`, and stride length by `12.24%`. At the same time, selected mechanics changed less, including `vertical_oscillation_cm` (`8.48%`) and `vertical_ratio_pct` (`-3.71%`).

The strongest within-subject adaptation-pathway signal was descriptively turnover-led change. Pace tracked cadence at `r = -0.9231`, compared with `r = -0.8205` for stride length, and cadence accounted for `62.4%` of the cadence-stride speed gain. The later window was also `100.0%` treadmill and showed markedly greater running specialization than the early window. This suggests that the system adapted through selective flexibility under specialization rather than uniform mechanical remodeling.

The study does not prove exact mechanism or direct difference from a non-compromised comparator system. It does, however, support a scientifically meaningful flagship conclusion: over six years, this altered system adapted substantially through phased ecological reconfiguration, treadmill-dominant specialization, and turnover-led running change, while selected movement features remained comparatively conserved.