diff --git a/src/builtins/crouch.rs b/src/builtins/crouch.rs
index 0752cb079..9a075352a 100644
--- a/src/builtins/crouch.rs
+++ b/src/builtins/crouch.rs
@@ -119,7 +119,7 @@ impl TnuaAction for TnuaBuiltinCrouch {
 
         let impulse_or_spring_force = |spring_offset: Float| -> TnuaVelChange {
             let spring_force = spring_force(spring_offset);
-            let spring_force_boost = spring_force.calc_boost(ctx.frame_duration);
+            let spring_force_boost = crate::util::calc_boost(&spring_force, ctx.frame_duration);
             let impulse_boost = self.impulse_boost(spring_offset);
             if spring_force_boost.length_squared() < impulse_boost.powi(2) {
                 TnuaVelChange::boost(impulse_boost * ctx.up_direction.adjust_precision())
diff --git a/src/builtins/knockback.rs b/src/builtins/knockback.rs
index c2266ef32..34ebe2dd9 100644
--- a/src/builtins/knockback.rs
+++ b/src/builtins/knockback.rs
@@ -108,7 +108,7 @@ impl TnuaAction for TnuaBuiltinKnockback {
                 if boundary.is_cleared() {
                     return TnuaActionLifecycleDirective::Finished;
                 } else {
-                    let regular_boost = motor.lin.calc_boost(ctx.frame_duration);
+                    let regular_boost = crate::util::calc_boost(&motor.lin, ctx.frame_duration);
                     if let Some((component_direction, component_limit)) = boundary
                         .calc_boost_part_on_boundary_axis_after_limit(
                             ctx.tracker.velocity,
diff --git a/src/util/mod.rs b/src/util/mod.rs
index 4bc835c4b..10a2222b2 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -147,3 +147,12 @@ pub fn rotation_arc_around_axis(
         Quaternion::from_rotation_arc_2d(Vector2::X, desired_forward_in_plane_coords);
     Some(rotation_to_set_forward.xyz().z)
 }
+
+/// Temporary until we get an official release of the physics integration layer crate with
+/// `calc_boost` in it.
+pub(crate) fn calc_boost(
+    vel_change: &bevy_tnua_physics_integration_layer::data_for_backends::TnuaVelChange,
+    frame_duration: Float,
+) -> Vector3 {
+    vel_change.acceleration * frame_duration + vel_change.boost
+}