diff --git a/python/README.md b/python/README.md
index 3968f6f..d8bdc86 100644
--- a/python/README.md
+++ b/python/README.md
@@ -19,6 +19,9 @@ it is still read.
 §5.1 still requires native `cadence` when rate is known; this library writes
 and reads both `cadence` and ID 93.
 
+`RecordingStrategy` includes TimeSampled (3). `StrokeState` (ID 96) is written
+only for that strategy: 0 Unknown, 1 Waiting, 2 Drive, 3 Dwell, 4 Recovery.
+
 Force is `AverageDriveForce` (6) and `PeakDriveForce` (7), in newtons. Fields 4
 and 5 are not part of this sample.
 
diff --git a/python/src/rowing_data/__init__.py b/python/src/rowing_data/__init__.py
index c794f8e..e37f188 100644
--- a/python/src/rowing_data/__init__.py
+++ b/python/src/rowing_data/__init__.py
@@ -6,6 +6,7 @@
     APPLICATION_UUID,
     PROTOCOL_VERSION,
     STANDARD_VERSION,
+    StrokeState,
 )
 from .fields import (
     DEVELOPER_FIELDS,
@@ -32,6 +33,7 @@
     "Record",
     "RowingSession",
     "STANDARD_VERSION",
+    "StrokeState",
     "decode",
     "encode",
     "field_by_id",
diff --git a/python/src/rowing_data/constants.py b/python/src/rowing_data/constants.py
index 9a0db92..8251245 100644
--- a/python/src/rowing_data/constants.py
+++ b/python/src/rowing_data/constants.py
@@ -38,3 +38,14 @@ class RecordingStrategy(IntEnum):
     UNKNOWN = 0
     STROKE_BOUNDARY = 1
     GPS_UPDATE = 2
+    TIME_SAMPLED = 3
+
+
+class StrokeState(IntEnum):
+    """Record developer field ID 96. Meaningful for TimeSampled files."""
+
+    UNKNOWN = 0
+    WAITING = 1
+    DRIVE = 2
+    DWELL = 3
+    RECOVERY = 4
diff --git a/python/src/rowing_data/fields.py b/python/src/rowing_data/fields.py
index dc1237d..955da4d 100644
--- a/python/src/rowing_data/fields.py
+++ b/python/src/rowing_data/fields.py
@@ -123,6 +123,7 @@ def _native(
     _dev(95, "WashThreshold", MessageType.SESSION, BaseType.UINT16, 1, "N"),
     _dev(19, "StrokeWork", MessageType.RECORD, BaseType.UINT16, 1, "J"),
     _dev(93, "StrokeRate", MessageType.RECORD, BaseType.UINT16, 100, "spm"),
+    _dev(96, "StrokeState", MessageType.RECORD, BaseType.UINT8, 1, ""),
 )
 
 NATIVE_FIELDS: tuple[FieldDef, ...] = (
diff --git a/python/src/rowing_data/model.py b/python/src/rowing_data/model.py
index fa60c6d..b1ca486 100644
--- a/python/src/rowing_data/model.py
+++ b/python/src/rowing_data/model.py
@@ -6,7 +6,7 @@
 from dataclasses import dataclass, field
 from datetime import datetime
 
-from .constants import RecordingStrategy
+from .constants import RecordingStrategy, StrokeState
 from .strokes import resolve_stroke_rate, stroke_counts
 
 
@@ -35,6 +35,7 @@ class Record:
     workout_state: int | None = None
     stroke_work_j: int | None = None
     stroke_rate: float | None = None
+    stroke_state: StrokeState | None = None
     lap_index: int | None = None
 
     def resolved_stroke_rate(self) -> float | None:
@@ -86,6 +87,7 @@ def stroke_counts(self) -> list[int]:
     (9, "workout_state"),
     (19, "stroke_work_j"),
     (93, "stroke_rate"),
+    (96, "stroke_state"),
 )
 
 ATTR_BY_FIELD_ID = dict(RECORD_DEVELOPER_ATTRS)
diff --git a/python/src/rowing_data/reader.py b/python/src/rowing_data/reader.py
index 3f5f596..6b6f87b 100644
--- a/python/src/rowing_data/reader.py
+++ b/python/src/rowing_data/reader.py
@@ -8,7 +8,12 @@
 from fitparse import FitFile
 
 from .codec import decode
-from .constants import APPLICATION_ID, PROTOCOL_VERSION, RecordingStrategy
+from .constants import (
+    APPLICATION_ID,
+    PROTOCOL_VERSION,
+    RecordingStrategy,
+    StrokeState,
+)
 from .fields import FieldDef, field_by_id, field_by_name
 from .model import ATTR_BY_FIELD_ID, Lap, Record, RowingSession
 from .validation import Issue
@@ -59,11 +64,22 @@ def read_fit(path: str | Path) -> RowingSession:
         break
 
     laps = _laps(messages)
-    records = tuple(
-        _record(message, our_fields, laps)
-        for message in messages
-        if message.name == "record"
-    )
+    records_list: list[Record] = []
+    for message in messages:
+        if message.name != "record":
+            continue
+        record, state_issue = _record(message, our_fields, laps)
+        records_list.append(record)
+        if state_issue is not None:
+            issues.append(
+                Issue(
+                    state_issue.level,
+                    state_issue.code,
+                    state_issue.message,
+                    len(records_list) - 1,
+                )
+            )
+    records = tuple(records_list)
     return RowingSession(
         records=records,
         recording_strategy=strategy,
@@ -204,7 +220,7 @@ def _recording_strategy(
         return RecordingStrategy.UNKNOWN, Issue(
             "warning",
             "recording_strategy",
-            f"RecordingStrategy {value} is not 0, 1, or 2; treating as Unknown",
+            f"RecordingStrategy {value} is not a known value; treating as Unknown",
         )
 
 
@@ -253,7 +269,9 @@ def _lap_index(timestamp: datetime, laps: list[Lap]) -> int | None:
     return index
 
 
-def _record(message, our_fields: dict[str, FieldDef], laps: list[Lap]) -> Record:
+def _record(
+    message, our_fields: dict[str, FieldDef], laps: list[Lap]
+) -> tuple[Record, Issue | None]:
     timestamp = _as_datetime(message.get_value("timestamp"))
     if timestamp is None:
         raise ValueError("record message is missing timestamp")
@@ -273,6 +291,7 @@ def _record(message, our_fields: dict[str, FieldDef], laps: list[Lap]) -> Record
         "lap_index": _lap_index(timestamp, laps),
     }
 
+    stroke_issue: Issue | None = None
     for field in message:
         if field.name in _NATIVE_NAMES or field.name in {"unknown", None}:
             continue
@@ -285,9 +304,36 @@ def _record(message, our_fields: dict[str, FieldDef], laps: list[Lap]) -> Record
         raw = field.raw_value
         if raw is None or isinstance(raw, list | tuple):
             continue
-        kwargs[attr] = decode(spec, int(raw))
+        decoded = decode(spec, int(raw))
+        if spec.field_id == 96:
+            decoded, state_issue = _as_stroke_state(decoded)
+            kwargs[attr] = decoded
+            stroke_issue = state_issue
+            continue
+        kwargs[attr] = decoded
+
+    return Record(**kwargs), stroke_issue  # type: ignore[arg-type]
 
-    return Record(**kwargs)  # type: ignore[arg-type]
+
+def _as_stroke_state(value: object) -> tuple[StrokeState | None, Issue | None]:
+    if value is None:
+        return None, None
+    try:
+        number = int(value)  # type: ignore[arg-type]
+    except (TypeError, ValueError):
+        return StrokeState.UNKNOWN, Issue(
+            "warning",
+            "stroke_state",
+            f"StrokeState {value!r} is unknown; treating as Unknown",
+        )
+    try:
+        return StrokeState(number), None
+    except ValueError:
+        return StrokeState.UNKNOWN, Issue(
+            "warning",
+            "stroke_state",
+            f"StrokeState {number} is above 4; treating as Unknown",
+        )
 
 
 def _native_int(message, name: str) -> int | None:
diff --git a/python/src/rowing_data/validation.py b/python/src/rowing_data/validation.py
index 438e469..9017d96 100644
--- a/python/src/rowing_data/validation.py
+++ b/python/src/rowing_data/validation.py
@@ -9,6 +9,7 @@
 from dataclasses import dataclass
 
 from .codec import CodecError, encode
+from .constants import RecordingStrategy
 from .fields import field_by_id, field_by_name
 from .model import NATIVE_RECORD_ATTRS, RECORD_DEVELOPER_ATTRS, Record, RowingSession
 
@@ -33,11 +34,11 @@ def validate(session: RowingSession) -> list[Issue]:
     """Return errors and warnings. Does not modify ``session``."""
     issues: list[Issue] = list(session.read_issues)
     for index, record in enumerate(session.records):
-        issues.extend(_record_issues(record, index))
+        issues.extend(_record_issues(record, index, session))
     return issues
 
 
-def _record_issues(record: Record, index: int) -> list[Issue]:
+def _record_issues(record: Record, index: int, session: RowingSession) -> list[Issue]:
     issues: list[Issue] = []
     for field_id, attr in RECORD_DEVELOPER_ATTRS:
         physical = getattr(record, attr)
@@ -70,6 +71,19 @@ def _record_issues(record: Record, index: int) -> list[Issue]:
         except CodecError as exc:
             issues.append(Issue("error", "overflow", str(exc), index))
 
+    if (
+        record.stroke_state is not None
+        and session.recording_strategy is not RecordingStrategy.TIME_SAMPLED
+    ):
+        issues.append(
+            Issue(
+                "warning",
+                "stroke_state",
+                "StrokeState is only meaningful when RecordingStrategy is TimeSampled",
+                index,
+            )
+        )
+
     if record.heart_rate == 0:
         issues.append(
             Issue(
diff --git a/python/src/rowing_data/writer.py b/python/src/rowing_data/writer.py
index 800dffe..b9c78df 100644
--- a/python/src/rowing_data/writer.py
+++ b/python/src/rowing_data/writer.py
@@ -28,7 +28,12 @@
 )
 
 from .codec import encode
-from .constants import APPLICATION_ID, CYCLE_LENGTH16_SCALE, PROTOCOL_VERSION
+from .constants import (
+    APPLICATION_ID,
+    CYCLE_LENGTH16_SCALE,
+    PROTOCOL_VERSION,
+    RecordingStrategy,
+)
 from .fields import BaseType, FieldDef, field_by_id, field_by_name
 from .model import (
     RECORD_DEVELOPER_ATTRS,
@@ -168,6 +173,9 @@ def _last_distance(session: RowingSession) -> float:
 def _record_developer_fields_used(session: RowingSession) -> tuple[FieldDef, ...]:
     used: list[FieldDef] = []
     for field_id, attr in RECORD_DEVELOPER_ATTRS:
+        time_sampled = session.recording_strategy is RecordingStrategy.TIME_SAMPLED
+        if field_id == 96 and not time_sampled:
+            continue
         if any(getattr(record, attr) is not None for record in session.records):
             used.append(field_by_id(field_id))
     return tuple(used)
diff --git a/python/tests/test_fields.py b/python/tests/test_fields.py
index 2f826b4..b7cfbd7 100644
--- a/python/tests/test_fields.py
+++ b/python/tests/test_fields.py
@@ -32,6 +32,7 @@
     (95, "WashThreshold", MessageType.SESSION, BaseType.UINT16, 1, "N", False),
     (19, "StrokeWork", MessageType.RECORD, BaseType.UINT16, 1, "J", False),
     (93, "StrokeRate", MessageType.RECORD, BaseType.UINT16, 100, "spm", False),
+    (96, "StrokeState", MessageType.RECORD, BaseType.UINT8, 1, "", False),
 )
 
 EXPECTED_NATIVE_SCALES = {
@@ -122,3 +123,4 @@ def test_recording_strategy_enum() -> None:
     assert RecordingStrategy.UNKNOWN == 0
     assert RecordingStrategy.STROKE_BOUNDARY == 1
     assert RecordingStrategy.GPS_UPDATE == 2
+    assert RecordingStrategy.TIME_SAMPLED == 3
diff --git a/python/tests/test_interop.py b/python/tests/test_interop.py
index 5652c86..3f19d4c 100644
--- a/python/tests/test_interop.py
+++ b/python/tests/test_interop.py
@@ -56,6 +56,7 @@ def test_rowingdata_golden_file_if_present() -> None:
         RecordingStrategy.UNKNOWN,
         RecordingStrategy.STROKE_BOUNDARY,
         RecordingStrategy.GPS_UPDATE,
+        RecordingStrategy.TIME_SAMPLED,
     }
     assert len(session.records) > 0
     # In-stroke curve fields are ignored; core metrics should still parse.
diff --git a/python/tests/test_reader.py b/python/tests/test_reader.py
index 8cafa4f..8507ca7 100644
--- a/python/tests/test_reader.py
+++ b/python/tests/test_reader.py
@@ -17,7 +17,7 @@
 from fit_tool.profile.profile_type import FileType, Manufacturer
 
 from rowing_data import APPLICATION_ID, read_fit, validate
-from rowing_data.constants import RecordingStrategy
+from rowing_data.constants import RecordingStrategy, StrokeState
 from rowing_data.fields import field_by_id
 
 
@@ -194,6 +194,52 @@ def test_mismatched_file_scale_warns_and_uses_v01_units(tmp_path: Path) -> None:
     assert any(issue.code == "field_scale" for issue in validate(loaded))
 
 
+def test_unknown_stroke_state_is_unknown(tmp_path: Path) -> None:
+    path = tmp_path / "phase.fit"
+    builder = FitFileBuilder(auto_define=True, min_string_size=64)
+    file_id = FileIdMessage()
+    file_id.type = FileType.ACTIVITY
+    file_id.manufacturer = Manufacturer.DEVELOPMENT
+    file_id.time_created = _ts_ms()
+    builder.add(file_id)
+    dev_id = DeveloperDataIdMessage()
+    dev_id.application_id = APPLICATION_ID
+    dev_id.developer_data_index = 0
+    builder.add(dev_id)
+    desc = FieldDescriptionMessage()
+    desc.developer_data_index = 0
+    desc.field_definition_number = 96
+    desc.fit_base_type_id = BaseType.UINT8.value
+    desc.field_name = "StrokeState"
+    desc.scale = 1
+    desc.offset = 0
+    desc.units = ""
+    builder.add(desc)
+    phase = DeveloperField(
+        developer_data_index=0,
+        field_id=96,
+        size=1,
+        name="StrokeState",
+        base_type=BaseType.UINT8,
+        scale=1,
+        offset=0,
+        units="",
+    )
+    phase.set_value(0, 9)
+    session = SessionMessage()
+    session.start_time = _ts_ms()
+    session.timestamp = _ts_ms()
+    builder.add(session)
+    rec = RecordMessage(developer_fields=[phase])
+    rec.timestamp = _ts_ms()
+    builder.add(rec)
+    builder.build().to_file(str(path))
+
+    loaded = read_fit(path)
+    assert loaded.records[0].stroke_state is StrokeState.UNKNOWN
+    assert any(issue.code == "stroke_state" for issue in loaded.read_issues)
+
+
 def test_invalid_recording_strategy_is_unknown_with_warning(tmp_path: Path) -> None:
     path = tmp_path / "bad_strategy.fit"
     builder = FitFileBuilder(auto_define=True, min_string_size=64)
@@ -229,7 +275,7 @@ def test_invalid_recording_strategy_is_unknown_with_warning(tmp_path: Path) -> N
         offset=0,
         units="",
     )
-    strategy.set_value(0, 3)
+    strategy.set_value(0, 9)
     session = SessionMessage(developer_fields=[strategy])
     session.start_time = _ts_ms()
     session.timestamp = _ts_ms()
diff --git a/python/tests/test_roundtrip.py b/python/tests/test_roundtrip.py
index 2d329a0..4aeca3e 100644
--- a/python/tests/test_roundtrip.py
+++ b/python/tests/test_roundtrip.py
@@ -8,7 +8,7 @@
 import pytest
 
 from rowing_data import read_fit, validate, write_fit
-from rowing_data.constants import RecordingStrategy
+from rowing_data.constants import RecordingStrategy, StrokeState
 from rowing_data.model import Record, RowingSession
 from sample_sessions import gps_update_session, stroke_boundary_session
 
@@ -42,6 +42,50 @@ def test_roundtrip_slip_and_wash_thresholds(tmp_path: Path) -> None:
     assert loaded.wash_threshold_n == 120
 
 
+def test_roundtrip_time_sampled_stroke_state(tmp_path: Path) -> None:
+    original = RowingSession(
+        recording_strategy=RecordingStrategy.TIME_SAMPLED,
+        records=(
+            Record(
+                timestamp=datetime(2026, 1, 1, tzinfo=UTC),
+                stroke_state=StrokeState.DRIVE,
+                total_cycles=1,
+            ),
+            Record(
+                timestamp=datetime(2026, 1, 1, 0, 0, 1, tzinfo=UTC),
+                stroke_state=StrokeState.RECOVERY,
+                total_cycles=1,
+            ),
+        ),
+    )
+    path = tmp_path / "time.fit"
+    write_fit(original, path)
+    loaded = read_fit(path)
+    assert loaded.recording_strategy is RecordingStrategy.TIME_SAMPLED
+    assert [record.stroke_state for record in loaded.records] == [
+        StrokeState.DRIVE,
+        StrokeState.RECOVERY,
+    ]
+
+
+def test_stroke_state_on_stroke_boundary_warns_and_is_omitted(tmp_path: Path) -> None:
+    session = RowingSession(
+        recording_strategy=RecordingStrategy.STROKE_BOUNDARY,
+        records=(
+            Record(
+                timestamp=datetime(2026, 1, 1, tzinfo=UTC),
+                stroke_state=StrokeState.DRIVE,
+            ),
+        ),
+    )
+    issues = validate(session)
+    assert any(issue.code == "stroke_state" for issue in issues)
+    path = tmp_path / "boundary.fit"
+    write_fit(session, path)
+    loaded = read_fit(path)
+    assert loaded.records[0].stroke_state is None
+
+
 def test_roundtrip_gps_update(tmp_path: Path) -> None:
     original = gps_update_session()
     path = tmp_path / "gps.fit"