Clinical implications from daily physiotherapy examination of 131 acute hamstring injuries and their association with running speed and rehabilitation progression

Key points

1. 01Outer range hamstring strength (as a percentage of the uninjured leg) best reflected both rehabilitation progression and perceived running effort among strength tests
2. 02MHFAKE (maximum hip flexion with active knee extension) outperformed the standard straight leg raise as a daily flexibility marker
3. 03Palpation pain length was usefully associated with rehabilitation progression, declining from a maximum early in recovery to zero by end of rehab
4. 04Daily pain scores typically normalised by about 30-40% of rehabilitation duration, limiting their usefulness in the second half of rehab
5. 05At perceived running efforts below about 40% of maximum, actual running speed varied so widely between individuals that the measure was clinically meaningless

How it was conducted

Design

Pooled cohort from two single-site prospective randomised controlled trials

Participants

131 male professional or competitive athletes with MRI-confirmed acute grade I or II hamstring injury

Setting

Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; data collected January 2011 to August 2016

Intervention

Standardised criteria-based staged physiotherapy rehabilitation protocol with daily clinical measurement

Primary outcomes

Association of daily clinical measures with (1) percentage of return-to-participation duration completed and (2) perceived running effort (0-100%)

Analysis

Univariate correlations (adjusted R2) using second-order polynomial fits; ICC and minimal detectable change for reliability

What they found

• Intrarater reliability was excellent for all strength and flexibility measures (lower bound of 95% CI never below 0.80 for any measure)
• Inner range strength intrarater ICC 0.87 (95% CI 0.84 to 0.89), MDC 4.9 kg (22.2% of mean)
• Mid-range strength intrarater ICC 0.89 (95% CI 0.87 to 0.90), MDC 5.6 kg (19.8% of mean)
• Outer range strength intrarater ICC 0.90 (95% CI 0.88 to 0.92), MDC 6.1 kg (18.5% of mean)
• SLR intrarater ICC 0.88 (95% CI 0.86 to 0.90), MDC 13.0 degrees (14.1% of mean)
• MHFAKE intrarater ICC 0.83 (95% CI 0.80 to 0.86), MDC 17.2 degrees (20.9% of mean)
• Inter-rater reliability was lower; inner range ICC 0.69 (95% CI 0.45 to 0.83), MHFAKE ICC 0.96 (95% CI 0.92 to 0.98)
• Variance in treatment progression explained (adjusted R2): daily pain 0.29, palpation pain length 0.18, SLR ROM 0.29, MHFAKE ROM 0.29, inner range strength 0.24, mid-range strength 0.27, outer range strength 0.27
• Variance in running progression explained (adjusted R2): MHFAKE ROM 0.35, outer range strength 0.34, mid-range strength 0.31, SLR ROM 0.20, daily pain 0.15, palpation pain length 0.05
• Mean return-to-participation duration was 23.9 (SD 10.8) days; 96.9% of athletes were professional level
• SLR flexibility normalised early, with very few subjects showing less than 90% of the uninjured leg within a few days of commencing rehabilitation, limiting its tracking utility
• At lower perceived running effort (below approximately 40% of maximum), variability in actual running speed was too great to be clinically meaningful; association improved at higher running intensities

Limitations

• All athletes followed the same criteria-based protocol at a single high-performance centre, limiting generalisability to community settings or athletes on different rehabilitation programmes
• Only univariate analyses were performed; multivariate combinations of measures may explain more variance
• Reliability data were collected on the uninjured leg only; no reliability data were available for palpation or subjective pain reports
• Running speed was timed with a handheld stopwatch, introducing measurement error compared with electronic timing

Why it matters

For patients

Athletes recovering from a hamstring strain can expect daily palpation, a specific active knee extension flexibility test, and outer range strength testing to be the most informative checks on how their rehabilitation is progressing.

For clinicians

A focused 5-minute daily assessment of palpation pain length, outer range strength percentage, MHFAKE percentage, and reported pain during activities provides the most useful information for progressing hamstring rehabilitation; the SLR can largely be dropped as a tracking tool.

For readers

This large prospective cohort provides normative trajectories and reliability benchmarks for daily hamstring assessment, supporting evidence-based selection of clinical tests over a full rehabilitation course.