TABLE II.

Data from Biopsy Samples^*

	Supraspinatus		Infraspinatus
	Intact	Torn	Intact	Torn
Diameter (mm)
Single fiber	0.120 ± 0.026†	0.074 ± 0.028†	0.098 ± 0.015†	0.103 ± 0.017†
Fiber bundle	0.365 ± 0.047†	0.400 ± 0.051†‡	0.337 ± 0.055†	0.465 ± 0.060†‡
Starting cross-sectional area (mm2)
Single fiber	0.006 ± 0.001†	0.004 ± 0.001†	0.010 ± 0.004†	0.010 ± 0.004†
Fiber bundle	0.113 ± 0.030†	0.143 ± 0.033†	0.086 ± 0.027†	0.141 ± 0.030†
Slack sarcomere length (μm)
Single fiber	1.96 ± 0.11	2.12 ± 0.12	2.06 ± 0.09	2.00 ± 0.10
Fiber bundle	2.09 ± 0.05	2.05 ± 0.06	2.08 ± 0.05	2.03 ± 0.06
Passive elastic modulus (kPa)
Single fiber	34.09 ± 4.72†	41.67 ± 5.18†‡	39.64 ± 4.71†	25.93 ± 5.16†‡
Fiber bundle	237.41 ± 59.78†§	515.74 ± 65.48†‡§	193.71 ± 34.96†	118.67 ± 38.29†‡
Fiber titin molecular weight (kDa)	3703.1 ± 16.1	3708.3 ± 19.7	3685.0 ± 20.5	3730.2 ± 25.0
Fiber bundle collagen (% wt/wt)	10.9 ± 3.1§	19.1 ± 2.3§	11.0 ± 4.0	17.2 ± 2.9

^*Values are given as the mean and standard error for three fibers or bundles per specimen from forty biopsy samples (twenty patients).

^†Significant difference between the single fiber and fiber-bundle data within the same muscle and injury group (p < 0.05).

^‡Significant difference between the supraspinatus and infraspinatus single fiber or fiber-bundle data when comparing the same parameter within the torn group (p < 0.05).

^§Significant difference between the data when comparing the same muscle group between the intact and torn groups (p < 0.05).