Specificity of resistance training responses in neck muscle size and strength.
Level 3 - non-randomized controlled study
Controlled trial without explicit mention of randomization in the abstract.
PubMed 9189733 · doi:10.1007/s004210050186
What was done
Twenty-two active college students (mean age 21 years, weight 71 kg) were assigned to one of three groups for 12 weeks: RESX (n = 8), performing multi-joint resistance training plus 3 sets of 10 repetitions of head extension 3 days per week at 3x10 repetition maximum (RM); RES (n = 6), performing only the multi-joint resistance exercises (squat, deadlift, push press, bent row, mid-thigh pull); or CON (n = 8), an untrained control group. Magnetic resonance imaging (MRI) of the cervical region assessed cross-sectional area (CSA) across four slices for nine muscle groups, and 3x10 RM head extension strength was measured.
What was found
Head extension 3x10 RM increased in RESX (from 17.9 [1.0] to 23.9 [1.4] kg, P < 0.05) but did not change in RES (17.6 [1.4] to 17.7 [1.9] kg) or CON (10.1 [2.2] to 10.3 [2.1] kg). Total neck muscle CSA increased in RESX (from 19.5 [3.0] to 22.0 [3.6] cm², P < 0.05), but not in RES (19.6 [2.9] to 19.7 [2.9] cm²) or CON (17.0 [2.5] to 17.0 [2.4] cm²). RESX hypertrophy was driven by CSA increases of 23.9 (3.2)% in splenius capitis, 24.0 (5.8)% in semispinalis capitis, and 24.9 (5.3)% in semispinalis cervicis. The RES group did experience training-induced hypertrophy elsewhere, showing a 7 (1)% increase in quadriceps femoris CSA (P < 0.05).
Why it matters
Heavy compound resistance exercises do not provide an adequate stimulus to increase cervical muscle size or strength; direct neck training is required for neck hypertrophy.
Limits
Small sample size (22 subjects total). The abstract does not state whether group assignment was randomized. The study evaluated only young, active college students and only tested sagittal-plane head extension, leaving other cervical movement planes unexamined.
Cited by
- supports A study showed that compound exercises like deadlifts, shrugs, and rows grew the trapezius muscles but did not grow the neck muscles, indicating direct neck flexion and extension training is required for neck muscle hypertrophy.