When you stretch a cold muscle you risk causing injuries which can range from minor strains to severe tears. (fitnessandpower.com)
Hamstring can be a few days or many many months — just depends on the severity — minor strain, major stain, minor tear, major tear, etc.. (justarsenal.com)
Cambridge have confirmed a strong squad to face the guest XV, including seven former Blues in what is their final match ahead of the Battle of the Blues, although captain Charlie Amesbury misses out due to a minor strain but is expected to be fully fit for the Twickenham showpiece. (thevarsitymatch.com)