TABLE 2.

Typical acute presentation and outcomes of hamstring strain injuries based on injury mechanism.⁷,⁸

Injury Mechanism	Ecchymosis	Straight Leg Raise Deficit*	Knee Flexion Strength Deficit*	Level of Pain	Site of Maximum Pain† (cm)	Length of Painful Area‡ (cm)	Median Time to Pre-Injury Level (wks)§
Running at maximal or near-maximal speed	minimal	40%	60%	moderate	12 ± 6 (range, 5-24)	11 ± 5 (range, 5-24)	16 (range, 6-50)
Movement involving extreme hip flexion and knee extension	none	20%	20%	minor	2 ± 1 (range, 1-3)	5 ± 2 (range, 2-9)	50 (range, 30-76)

^*percent deficit of injured limb compared to non-injured limb

^†distance from point of maximum palpatory pain to the ischial tuberosity

^‡measured in cranial-caudal direction

^§time needed for athletic performance to return to pre-injury level