Isometric strength of neck flexors scored significantly different compared to baseline measurement ( mean 30.0 seconds , sd :25.2 ) , and increased with a mean difference of 17.33 seconds ( 95 % CI : 20.61 to 14.05 ) at 8 weeks and 19.18 seconds ( 95 % CI : 23.48 to 14.87 ) at 26 weeks .