Frequency and Volume of Resistance Training: Effect on Cervical Extension Strength


The MedX Cervical Extension Machine was developed to satisfy four primary factors necessary for accurate and reliable assessment of cervical extension strength: (1) isolation of the active musculature via torso stabilization; (2) measurement of full range of motion (ROM) cervical extension muscles (CERV EXT) strength; (3) compensation for the influence of gravitational forces acting on the head and neck; and (4) standardization of position and procedures. The general recommendation of this machine was to train with greater frequency and volume (2x or 3x/wk); the purpose of this study was to investigate the effect of frequency and volume training on CERV EXT strength. The findings are intended to aid clinicians in making recommendations for CERV EXT training.


50 men and 28 women volunteered to participate in this study; subjects were randomly assigned to one of four training groups or a control group that did not train. The training groups exercised for 12 weeks doing either: once per week using one set of dynamic exercise (DYN), once per week using one set of DYN and one set of maximal isometric (IM) exercise at eight angles through a 126°-range of CERV EXT, DYN twice per week, or DYN and IM twice per week. Maximal IM torque was measured at eight angles initially and after 12 weeks of training. All training groups improved CERV EXT strength at all angles tested compared to the control group except for DYN once per week at 0° of CERV flexion. A greater increase in strength was found when the groups that trained two times a week were compared to those that trained once per week. The results indicate that only a single set of CERV EXT exercise is required to attain a full range-of-motion increase in strength as long as the training frequency is at least two times per week.

Key Findings

  • Increases in maximum IM torque at full cervical flexion ranged from 13% to 41% in all training groups
  • Strength gaines at teh most extended position ranged from 6% to 20%
  • All four training groups exhibited marked improvement in DYN strength gain

Keywords: Cervical extension, MedX Cervical Extension Machine, strength, dynamic exercise, maximal isometric exercise

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