REF-1351 · Warren, Lowe & Armstrong, 1999 · Sports Medicine · Paper · PubMed

Is CK or soreness a good way to tell how damaged my legs are?

No: this review rates maximal strength and range of motion best for sizing eccentric muscle injury and advises against soreness and blood muscle proteins (CK is one).

Main caveat: Read from the abstract only; the studies evaluated, any reliability data and the reasoning behind each ranking could not be checked.
moderate evidenceMeasured on non-athletes and recreational people

Warren, Lowe and Armstrong evaluated the measures then used in studies of eccentric contraction-induced muscle injury, asking which best quantify how large the injury is, how long it lasts, and how well each indicates functional loss.

For human studies they concluded that maximal voluntary contraction torque and range of motion are the best ways to quantify injury; for animal studies, electrically evoked isometric force measured in vitro.

They recommended that future work measure more of the contractile picture — force-velocity and force-length relationships, maximal shortening velocity and susceptibility to fatigue — and that histology, soreness ratings and blood or bath levels of muscle proteins be discouraged as ways to quantify injury or functional impairment.

Our reading: this is the methods basis for the base's rule that strength loss, not creatine kinase (CK) or soreness, sizes damage — later restated in REF-1347 (strength loss "the best indirect marker") and consistent with the spread of CK between people in REF-305, REF-1349 and REF-1350.

It does not say these markers are useless for other purposes, only that they should not be used to measure the injury.

Protocol

Design: narrative review of measurement tools in human and animal studies of eccentric injury; the abstract gives no search method, study count or numbers.
Criteria used: usefulness for quantifying the magnitude and duration of the injury, and as indicators of functional deficits (abstract).
Sample: n = not applicable (narrative review; no studies counted in the abstract).
Funding and interests: the paper's own acknowledgement could not be read; the PubMed and Europe PMC record lists NIA (NIH) grant F32 AG005815. No industry funding appears in the record.

Key Results

SettingBest measures (authors' evaluation)Measures to discourage for quantifying injuryRecommended for future work
Human studiesmaximal voluntary contraction torque; range of motionhistology; soreness ratings; blood levels of myofibre proteins (such as CK)force/torque-velocity and force/torque-length relationships, maximal shortening velocity, fatigue susceptibility
Animal studiesin vitro electrically elicited isometric forcehistology; bath levels of myofibre proteinsthe same contractile parameters
The abstract reports no reliability or validity statistics and no study-by-study comparison.

Mechanisms

Authors' interpretation: the injury that matters is the loss of function, so the best measures are those that read function directly — force and range of motion — while tissue samples, symptoms and enzymes in blood track it poorly.
Inference: blood CK is the net of release and clearance and differs widely between people on the same protocol (REF-1350, REF-305), and soreness correlates poorly with the other markers (REF-1347); both explain why neither sizes the damage.

Practical Application

Is CK or soreness a good way to tell how damaged my legs are? No: this review rates maximal strength and range of motion best for sizing eccentric muscle injury and advises against soreness and blood muscle proteins (CK is one).
In the field, use a function check, not a blood test (inference; the abstract names only laboratory torque and range of motion): how a known effort or a repeatable jump goes says more about the state of the muscle than CK or soreness.In the base, after a marathon, CK and LDH recovered no differently with easy running, elliptical work or rest, while the squat jump of the running group was better than the rest group's at 96 h (REF-761) — the function measure separated what the markers did not.
Readiness decisions: the base judges readiness by function, feel and how a known session goes (SYNTH-70) and keeps sprints and max tests off fresh damage (SYNTH-23); this review is the methods reason those rules lean on function.
What it is good for as a source: the statement that force loss is the best measure of eccentric damage and that soreness, histology and blood proteins should not be used to quantify it. Not for thresholds, time courses or field-test validity.

Limitations

Read from the abstract only; the studies evaluated, any reliability data and the reasoning behind each ranking could not be checked.
Narrative review from 1999 without a systematic method; the ranking is the authors' judgement.
Laboratory measures: maximal voluntary torque on a dynamometer and range of motion; field tests are not covered in the abstract.
Funding: from the record (NIA grant F32 AG005815), not from the paper's acknowledgement.
How this entry was checked and changed
Why this level

an authoritative review from the leading eccentric-injury laboratory of its time (R.B. Armstrong's Muscle Biology Laboratory, Texas A&M; his 1984 review of exercise-induced muscle soreness is still cited in REF-1347, which also cites this review); held at B+ because it has no systematic method and its ranking is the authors' evaluation, not a head-to-head comparison of the measures; read from the abstract only (no Europe PMC copy, no repository copy listed by OpenAlex)