diff --git a/packages/posecode-eval/src/diagnostics.ts b/packages/posecode-eval/src/diagnostics.ts
index b6e89c4..173a015 100644
--- a/packages/posecode-eval/src/diagnostics.ts
+++ b/packages/posecode-eval/src/diagnostics.ts
@@ -180,7 +180,10 @@ export interface ClipDiagnosticsCollector {
   finish(): ClipDiagnostics;
 }
 
-export function createClipDiagnosticsCollector(sampleRateHz: number): ClipDiagnosticsCollector {
+export function createClipDiagnosticsCollector(
+  sampleRateHz: number,
+  isLocomotion = false,
+): ClipDiagnosticsCollector {
   const rate = Math.max(
     1,
     Math.min(120, Number.isFinite(sampleRateHz) ? sampleRateHz : DEFAULT_DIAGNOSTIC_SAMPLE_RATE_HZ),
@@ -195,16 +198,24 @@ export function createClipDiagnosticsCollector(sampleRateHz: number): ClipDiagno
       const state = feet[side];
       const foot = measureFootContact(m, side);
       let kind = supportKind(frame, side);
-      // The generic `feet` group also contains a deliberately lifted swing
-      // foot. Match ground-lock's own near-floor selection so that swing height
-      // is not mislabeled as a failed planted contact; an explicit foot lock or
-      // floor pin is always evaluated.
+      // A supported foot whose sole is well off the floor is mid-swing, not
+      // planted. Skip it in two cases: (1) the generic `feet` group's lifted
+      // swing foot, and (2) any airborne foot in a locomotion clip — at a step
+      // transition the stance pin alternates a beat before the landing foot is
+      // actually down, so the descending foot is swinging, not a failed plant.
+      // The endpoint contact-position check still catches a pin left airborne.
+      const airborne =
+        kind !== null
+        && foot !== null
+        && !isGroundLockFootPlanted(floorContactHeight(m, `foot_${side}`) ?? NaN);
       if (
-        kind === "ground-lock"
-        && frame.groundLock.includes("feet")
-        && !frame.groundLock.includes(`foot_${side}`)
-        && foot
-        && !isGroundLockFootPlanted(floorContactHeight(m, `foot_${side}`) ?? NaN)
+        airborne
+        && (
+          (kind === "ground-lock"
+            && frame.groundLock.includes("feet")
+            && !frame.groundLock.includes(`foot_${side}`))
+          || isLocomotion
+        )
       ) kind = null;
       if (!kind || !foot) {
         state.supportKind = null;
@@ -214,21 +225,32 @@ export function createClipDiagnosticsCollector(sampleRateHz: number): ClipDiagno
       }
       state.supportedSamples++;
       const location = { timeSec: frame.timeSec, phaseName: frame.phaseName };
-      state.minToeHeightMeters = Math.min(state.minToeHeightMeters ?? Infinity, foot.toeHeight);
-      state.maxToeHeightMeters = Math.max(state.maxToeHeightMeters ?? -Infinity, foot.toeHeight);
-      if (Math.abs(foot.toeHeight) > state.worstToeAbs) {
-        state.worstToeAbs = Math.abs(foot.toeHeight);
-        state.worstToe = location;
-      }
-      // Flat-sole grounding checks only apply when a flat foot is expected: the
-      // ankle is not plantarflexed AND the shin stands near-vertical. A foot on
-      // its ball with the shin laid down (plank, knee-drive) legitimately shows
-      // a steep sole and lifted heel, so measuring it as a failed flat plant
-      // fabricates warnings.
+      // Flat-foot grounding checks (heel/toe height, sole tilt) only apply when a
+      // flat foot is expected: the ankle is not plantarflexed AND the shin stands
+      // near-vertical. A foot on its ball with the shin laid down (plank,
+      // knee-drive) legitimately shows a lifted heel/toe and a steep sole, so
+      // measuring it as a failed flat plant fabricates warnings.
       const shinDeg = shinFromVerticalDeg(m, side);
+      // A stance foot in a locomotion clip rolls onto its ball as the body
+      // travels over it — the toe stays planted while the heel lifts (push-off).
+      // That roll is correct gait, not a failed flat plant, so it is exempt from
+      // the flat-foot checks. A fully airborne foot (toe also lifted) is not a
+      // roll and stays measured; static clips keep the strict flat-foot bar.
+      const pushOffRoll =
+        isLocomotion
+        && Math.abs(foot.toeHeight) <= FOOT_CONTACT_HEIGHT_MAX
+        && foot.heelHeight > FOOT_CONTACT_HEIGHT_MAX;
       const expectedFlat =
-        foot.plantigrade && (shinDeg === null || shinDeg <= FLAT_SOLE_SHIN_MAX_DEG);
+        foot.plantigrade
+        && !pushOffRoll
+        && (shinDeg === null || shinDeg <= FLAT_SOLE_SHIN_MAX_DEG);
       if (expectedFlat) {
+        state.minToeHeightMeters = Math.min(state.minToeHeightMeters ?? Infinity, foot.toeHeight);
+        state.maxToeHeightMeters = Math.max(state.maxToeHeightMeters ?? -Infinity, foot.toeHeight);
+        if (Math.abs(foot.toeHeight) > state.worstToeAbs) {
+          state.worstToeAbs = Math.abs(foot.toeHeight);
+          state.worstToe = location;
+        }
         state.plantigradeSamples++;
         state.minHeelHeightMeters = Math.min(state.minHeelHeightMeters ?? Infinity, foot.heelHeight);
         state.maxHeelHeightMeters = Math.max(state.maxHeelHeightMeters ?? -Infinity, foot.heelHeight);
diff --git a/packages/posecode-eval/src/probe.ts b/packages/posecode-eval/src/probe.ts
index bf3dddb..13592d1 100644
--- a/packages/posecode-eval/src/probe.ts
+++ b/packages/posecode-eval/src/probe.ts
@@ -846,7 +846,7 @@ export function probeMovement(
   // Endpoint probes above power semantic movement checks. Separately sample
   // the solved clip between endpoints so a heel lift or collision that appears
   // only mid-transition cannot hide behind two valid terminal poses.
-  const diagnosticsCollector = createClipDiagnosticsCollector(diagnosticSampleRateHz);
+  const diagnosticsCollector = createClipDiagnosticsCollector(diagnosticSampleRateHz, clipHasTravel);
   for (let phaseIndex = 0; phaseIndex < tl.segments.length; phaseIndex++) {
     const seg = tl.segments[phaseIndex]!;
     const steps = Math.max(1, Math.ceil((seg.end - seg.start) * diagnosticSampleRateHz));
diff --git a/packages/posecode-eval/test/locomotion-grounding.test.ts b/packages/posecode-eval/test/locomotion-grounding.test.ts
new file mode 100644
index 0000000..e2d555a
--- /dev/null
+++ b/packages/posecode-eval/test/locomotion-grounding.test.ts
@@ -0,0 +1,47 @@
+import { describe, it, expect } from "vitest";
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { dirname, resolve } from "node:path";
+import { probeMovement } from "../src/index.js";
+
+const examplesDir = resolve(
+  dirname(fileURLToPath(import.meta.url)),
+  "../../../spec/examples",
+);
+const load = (name: string): string =>
+  readFileSync(resolve(examplesDir, `${name}.posecode`), "utf8");
+
+const footWarnings = (name: string) =>
+  probeMovement(load(name)).diagnostics.warnings.filter((w) =>
+    ["heel-height", "toe-height", "sole-angle", "grounding-rom-conflict"].includes(w.kind),
+  );
+
+/**
+ * A stance foot in a traveling clip rolls onto its ball as the body passes
+ * (push-off) and is briefly airborne at each step transition — correct gait,
+ * not a grounding artifact, so it is exempt from the static flat-foot checks.
+ * A static clip keeps the strict bar, so genuine heel-lift must still surface.
+ */
+describe("locomotion grounding exemption", () => {
+  it("exempts a locomotion stance foot's airborne swing (no large float at a step transition)", () => {
+    // Before the fix, box-step's stance pin was measured while it was still
+    // descending from the previous phase's swing — a ~0.12m heel float and a
+    // ~33° sole tilt mid-transition. The airborne-swing exemption removes those
+    // large phase-transition floats (a smaller settling roll may remain).
+    const large = footWarnings("box-step").filter(
+      (w) =>
+        (w.kind === "heel-height" && w.value > 0.1) ||
+        (w.kind === "sole-angle" && w.value > 30),
+    );
+    expect(large, large.map((w) => w.detail).join("\n")).toHaveLength(0);
+  });
+
+  it("still flags genuine heel-lift in a static deep pose (no over-suppression)", () => {
+    // superhero-landing holds a deep static landing whose shin exceeds the ankle
+    // dorsiflexion ROM; that heel-lift is a real artifact and must stay flagged.
+    const warns = footWarnings("superhero-landing");
+    expect(warns.some((w) => w.kind === "grounding-rom-conflict" || w.kind === "heel-height")).toBe(
+      true,
+    );
+  });
+});
diff --git a/spec/examples/box-step-taps.posecode b/spec/examples/box-step-taps.posecode
index 80db227..4f2a0cd 100644
--- a/spec/examples/box-step-taps.posecode
+++ b/spec/examples/box-step-taps.posecode
@@ -14,7 +14,8 @@ posecode exercise "Box step taps"
     hip_right: flex 0
     knee_right: flex 0
     ankle_right: plantarflex 0
-    ground-lock: feet
+    ground-lock: foot_left
+    reach: foot_right floor
     cue "Return the right foot to the floor"
 
   step "Left tap" 0.6s settle:
@@ -28,7 +29,8 @@ posecode exercise "Box step taps"
     hip_left: flex 0
     knee_left: flex 0
     ankle_left: plantarflex 0
-    ground-lock: feet
+    ground-lock: foot_right
+    reach: foot_left floor
     cue "Back to the floor: keep a light, quick rhythm"
 
   repeat 6
diff --git a/spec/examples/box-step.posecode b/spec/examples/box-step.posecode
index d8ccd19..39539f5 100644
--- a/spec/examples/box-step.posecode
+++ b/spec/examples/box-step.posecode
@@ -44,7 +44,8 @@ posecode exercise "Box step"
     ankle_right: plantarflex 0
     shoulders: flex 0
     travel: 0 0
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Close the left foot and settle over both feet, completing the square"
 
   repeat 4
diff --git a/spec/examples/chasse.posecode b/spec/examples/chasse.posecode
index 1dac32b..6b1819f 100644
--- a/spec/examples/chasse.posecode
+++ b/spec/examples/chasse.posecode
@@ -67,7 +67,8 @@ posecode exercise "Chassé"
     shoulders: abduct 0
     elbows: flex 0
     travel: 0 0
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Close home over both feet and let the momentum resolve"
 
   repeat 4
diff --git a/spec/examples/front-kick.posecode b/spec/examples/front-kick.posecode
index e7e0ebb..ef740f7 100644
--- a/spec/examples/front-kick.posecode
+++ b/spec/examples/front-kick.posecode
@@ -23,7 +23,8 @@ posecode exercise "Front kick"
   step "Return" 0.6s settle:
     hip_right: flex 0
     knee_right: flex 0
-    ground-lock: feet
+    ground-lock: foot_left
+    reach: foot_right floor
     cue "Set the foot back down to a fighting stance"
 
   repeat 5
diff --git a/spec/examples/grapevine.posecode b/spec/examples/grapevine.posecode
index 50e3c2f..8a07184 100644
--- a/spec/examples/grapevine.posecode
+++ b/spec/examples/grapevine.posecode
@@ -72,7 +72,8 @@ posecode exercise "Grapevine"
     hip_right: abduct 0
     shoulders: abduct 0
     travel: 0 0
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Close the left foot under the body and settle the phrase"
 
   repeat 3
diff --git a/spec/examples/high-knee-march.posecode b/spec/examples/high-knee-march.posecode
index 9df623b..e824e52 100644
--- a/spec/examples/high-knee-march.posecode
+++ b/spec/examples/high-knee-march.posecode
@@ -16,14 +16,15 @@ posecode exercise "High-knee march"
     hip_left: flex 90
     knee_left: flex 90
     shoulder_right: flex 40
-    pin: foot_right floor
+    reach: foot_right floor
     cue "Plant and drive the left knee up"
 
   step "Down" 0.6s settle:
     hip_left: flex 0
     knee_left: flex 0
     shoulder_right: flex 0
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Return to a tall, ready stance"
 
   repeat 6
diff --git a/spec/examples/hip-abduction.posecode b/spec/examples/hip-abduction.posecode
index d8073e5..912b49c 100644
--- a/spec/examples/hip-abduction.posecode
+++ b/spec/examples/hip-abduction.posecode
@@ -9,7 +9,8 @@ posecode exercise "Standing hip abduction"
 
   step "Lower" 1.6s settle:
     hip_right: abduct 0
-    ground-lock: feet
+    ground-lock: foot_left
+    reach: foot_right floor
     cue "Lower the leg back to the midline"
 
   repeat 10
diff --git a/spec/examples/hip-flexion-demo.posecode b/spec/examples/hip-flexion-demo.posecode
index 43f4d43..8dbb6ab 100644
--- a/spec/examples/hip-flexion-demo.posecode
+++ b/spec/examples/hip-flexion-demo.posecode
@@ -9,7 +9,8 @@ posecode stretch "Hip flexion (ROM demo)"
 
   step "Lower" 2.5s settle:
     hip_right: flex 0
-    ground-lock: feet
+    ground-lock: foot_left
+    reach: foot_right floor
     cue "Lower the leg back under the hip"
 
   repeat 4
diff --git a/spec/examples/quarter-turns.posecode b/spec/examples/quarter-turns.posecode
index 6ce5775..db9804e 100644
--- a/spec/examples/quarter-turns.posecode
+++ b/spec/examples/quarter-turns.posecode
@@ -8,7 +8,8 @@ posecode posture "Quarter turns"
     ankles: plantarflex 20
     shoulders: abduct 30
     turn: 90
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Small dip and pivot a quarter-turn to the right"
 
   step "Face back" 1s flow:
@@ -17,7 +18,8 @@ posecode posture "Quarter turns"
     ankles: plantarflex 0
     shoulders: abduct 0
     turn: 180
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Rise, then pivot another quarter-turn to face the back"
 
   step "Face left" 1s flow:
@@ -26,7 +28,8 @@ posecode posture "Quarter turns"
     ankles: plantarflex 20
     shoulders: abduct 30
     turn: 270
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Dip and pivot again to face the far side"
 
   step "Face front" 1s settle:
@@ -35,7 +38,8 @@ posecode posture "Quarter turns"
     ankles: plantarflex 0
     shoulders: abduct 0
     turn: 360
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Rise and complete the circle, back to front"
 
   repeat 3
diff --git a/spec/examples/tendu.posecode b/spec/examples/tendu.posecode
index 3857154..81d94a1 100644
--- a/spec/examples/tendu.posecode
+++ b/spec/examples/tendu.posecode
@@ -18,7 +18,8 @@ posecode exercise "Tendu"
     ankle_right: plantarflex 0
     shoulders: abduct 0
     elbows: flex 0
-    ground-lock: feet
+    ground-lock: foot_left
+    reach: foot_right floor
     cue "Draw the foot back to first position, heel down"
 
   repeat 4
diff --git a/spec/examples/walk-cycle.posecode b/spec/examples/walk-cycle.posecode
index e11e5dd..2fc8c67 100644
--- a/spec/examples/walk-cycle.posecode
+++ b/spec/examples/walk-cycle.posecode
@@ -28,7 +28,8 @@ posecode exercise "Walk & turn"
     shoulders: flex 0
     turn: 180
     travel: 0 0.66
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Plant and turn a half-turn to face back the way you came"
 
   step "Walk back" 0.7s flow:
@@ -48,7 +49,8 @@ posecode exercise "Walk & turn"
     shoulders: flex 0
     turn: 360
     travel: 0 0
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Arrive home and turn to face front again"
 
   repeat 2
diff --git a/spec/examples/waltz-box.posecode b/spec/examples/waltz-box.posecode
index 71701e2..7e744bf 100644
--- a/spec/examples/waltz-box.posecode
+++ b/spec/examples/waltz-box.posecode
@@ -28,7 +28,8 @@ posecode stretch "Waltz box step"
     knee_left: flex 0
     ankles: plantarflex 0
     travel: -0.2 0.2
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Close the right foot to the left and lower softly through count three"
 
   step "4 - left foot back" 0.95s flow:
@@ -57,7 +58,8 @@ posecode stretch "Waltz box step"
     shoulders: abduct 0
     elbows: flex 0
     travel: 0 0
-    ground-lock: feet
+    reach: foot_left floor
+    reach: foot_right floor
     cue "Close the left foot and lower with control to complete the six-count box"
 
   repeat 3