Table 2. Evaluating the Strain Stiffening Behavior by Model Fitting.

		Linear Model Parameters			Hill Model Parameters
Treatment	Best Model	β	c	RSS	α	λ	RSS
3 d Con	Hill	6.32e-6	0.060	0.0502	0.133	1653	0.0478
3 d GA	Hill	7.54e-6	0.067	0.0351	0.157	1856	0.0285
Uni	Hill	6.81e-6	0.033	0.0057	0.124	3049	0.0041

Model comparisons of linear versus Hill-type equation were performed for the oscillation data on the 3 DAS samples for the different treatments. The linear model has the form , and the Hill model has the form , where Σ = strain and F = force. The model fitting is done using the nonlinear least squares method in R. As both models have two free parameters, the model that best fits the data is selected based on it having the smallest RSS (underlined).