The Reliability and Validity of Manual Palpation to Assess Lower Limb Arterial Occlusion Pressure in Older Adults, for Application in Blood Flow Restriction Exercise.

(A) Investigate test-retest reliability of posterior tibial pulse palpation to determine arterial occlusion pressure (AOP) and examine validity against hand-held Doppler ultrasound. (B) Investigate the suitability of using 130% systolic brachial blood pressure for prescribing cuff inflation pressure for blood flow restriction (BFR) exercise. Repeated measures, crossover design. Lower limb AOP was assessed in 20 adults ≥ 60 years using hand-held Doppler ultrasound and posterior tibial pulse palpation. Brachial systolic blood pressure (bSBP) was measured to predict cuff inflation pressures (bSBP130%). On three occasions > 24 hours apart, three AOP measurements were recorded by the same blinded rater to determine intra-rater reliability. Participants lay supine, with arterial occlusion achieved using a rapid inflation system and a 10-cm cuff. Reliability was assessed via intraclass correlation coefficients (ICC), coefficients of variation (CV) and Bland-Altman plots, with validity examined via Pearson's product-moment correlations and Bland-Altman plots. Good to excellent reliability was observed for AOP assessed with Doppler ultrasound (ICC = 0.91, CV = 5.4%) and palpation (ICC = 0.91, CV = 5.8%). A strong positive correlation was observed in AOP values between methods (r = 0.85-0.92, p < 0.001), though palpation significantly underestimated AOP compared to Doppler ultrasound (-11.8 mmHg ± 8.32; p < 0.001). bSBP130% was not different to 100% AOP determined with hand-held Doppler (p = 0.516). Palpation may provide a reliable and clinically acceptable alternative to hand-held Doppler ultrasound for assessing lower limb AOP for blood flow restriction exercise. Employing bSBP130% may result in complete arterial occlusion with a 10 cm cuff, which is not supported by current BFR exercise recommendations for sub-occlusive pressures.