Results of neck-specific exercise for altered postural sway in chronic whiplash-associated disorders: a longitudinal case-control study

Key points

1. 01People with chronic WAD showed significantly worse postural sway than healthy matched controls in double-stance eyes-closed testing at baseline, but not in single-leg eyes-open testing
2. 02After 12 weeks of neck-specific exercise, the WAD group's double-stance pathway and single-leg pathway sway improved significantly and group differences versus controls were no longer significant
3. 03The exercise programme targeted deep and superficial neck muscles progressively, with four physiotherapist visits plus an online component or twice-weekly clinic sessions
4. 04Self-reported balance problems correlated moderately with objective sway measures, but self-reported dizziness during motion did not correlate with any sway test
5. 05The study is a pilot longitudinal case-control design without a non-exercise control arm, limiting causal conclusions

How it was conducted

Design

Longitudinal prospective experimental case-control intervention study

Participants

30 adults with chronic WAD grades 2-3 (mean age 40.6 years, 75% female, mean 26.5 months post-injury) and 30 age- and gender-matched healthy controls

Intervention

12-week neck-specific exercise programme (NSEIT or NSE) targeting deep and superficial neck muscles with progressive loading

Primary outcome

Postural sway pathway and 95% ellipse area in double-stance eyes-closed, measured via a validated iPhone accelerometer application at the pelvis

Secondary outcome

Postural sway in single-leg stance eyes-open; self-rated dizziness during motion and balance problems on VAS

Follow-up

Baseline and 3-month (end of intervention)

What they found

• WAD group showed greater double-stance eyes-closed pathway than controls at baseline: 24.85 cm (SD 10.78) vs 17.84 cm (SD 5.27), difference 7.0 cm, p = 0.003, effect size 0.78
• WAD group showed greater double-stance eyes-closed ellipse area than controls at baseline: 0.45 cm2 (SD 0.58) vs 0.15 cm2 (SD 0.15), difference 0.30 cm2, p = 0.006, effect size 0.73
• WAD group improved significantly in double-stance eyes-closed pathway from baseline to 3 months: change -4.25 cm (SD 13.4), p = 0.029, effect size 0.32
• WAD group improved significantly in single-leg eyes-open pathway from baseline to 3 months: change -7.28 cm (SD 18.7), p = 0.037, effect size 0.39
• Ellipse area double-stance eyes-closed decreased by -0.24 cm2 (SD 0.58) at 3 months but was non-significant (p = 0.065, effect size 0.42)
• At 3-month follow-up, between-group difference in double-stance pathway was no longer significant: WAD 21.48 cm vs control 17.84 cm, p = 0.238
• Self-rated balance problems correlated with double-stance pathway (r = 0.39, p = 0.05), single-leg pathway (r = 0.49, p < 0.01), and single-leg ellipse area (r = 0.44, p < 0.01)
• Dizziness during motion did not correlate with any postural sway measure (r = -0.08 to 0.27, p > 0.05)
• 62% of WAD participants reported high exercise compliance (>80%), 24% medium, 14% low

Limitations

• No non-exercise control group for the WAD participants, so natural recovery cannot be ruled out
• Small sample size (n = 30 per group) was not power-calculated for postural sway outcomes; the study is exploratory and authors acknowledge it may be underpowered for single-leg stance
• Technical data loss at follow-up (missing data from 8-9 participants in some conditions) and exclusion of two outliers may affect precision
• Static postural sway does not capture dynamic balance challenges relevant to daily life, such as walking or head-turning tasks

Why it matters

For patients

People recovering from chronic whiplash may expect meaningful improvements in their balance and unsteadiness after completing a dedicated neck muscle exercise programme.

For clinicians

Neck-specific exercise targeting deep and superficial cervical muscles appears capable of reducing objective postural sway in WAD grades 2-3, supporting its inclusion in rehabilitation programmes for this group, pending confirmation in RCTs.

For readers

This pilot case-control study provides preliminary evidence that neck proprioceptive deficits driving poor eyes-closed balance in chronic WAD are reversible with targeted exercise, and that a smartphone application can serve as a practical clinical balance measure.