Effects of neck muscle training and their changes after discontinuation of training (detraining) were studied in 22 athletes (college American football players) and 19 non-athletes. The subjects underwent narrow grip shoulder shrug training using free weights (NGSS group), isometric training of the neck in pairs (PAIR group), or both types of training (COMB group) for 14 weeks, and were then detrained during the following 14 weeks. Extension and flexion muscle strength (maximum isometric muscle strength) of the neck were measured using a method in which subjects pulled a wire attached over the head in a sitting position at 2-week intervals after the start of training.The following results were obtained.
1. In the athletes, the flexion muscle strength increased by 16.9±5.6% (mean±standard deviation) in the COMB group and by 14.8±5.2% in the NGSS group, and the increases in these groups were significantly greater than the increase in the PAIR group (p<0.01) . The extension muscle strength also increased, most notably in the COMB group (12.2±4.7%) .
2. In the non-athletes, the flexion muscle strength increased by 29.4±7.2% in the COMB group, and this increase was significantly greater than that in the PA1R group (p<0.01) . This increase was also significantly greater than that in the COMB group of the athletes (p<0.01) . The extension muscle strength increased by 19.1±5.2% in the COMB group.
3. In the athletes, the flexion muscle strength of the COMB group was increased by 8.3% after 14 weeks of training and 14 weeks of detraining as compared with that at the start of training. In the non-athletes, the flexion and extension muscle strength of the COMB group increased by 17.4% and 9.8%, respectively, after the start of training.
These results suggest that narrow grip shoulder shrug training used for the development of muscle strength in the lower neck is effective for improving flexion as well as extension muscle strength, and that the decrease in muscle strength due to detraining can be reduced by combining this training with isometric training performed by the PAIR group.