Manual pressure or Helfer (rhythmic) tapping techniques over the injection site reduced intramuscular injection-associated pain in adults, concluded a study issued in Public Library of Science One. To examine the effect of different intramuscular injection techniques on injection-linked pain, various databases such as MEDLINE, EMBASE, British Nursing Index, and CINAHL were explored. 

In this systematic review and meta-analysis, Oluseyi Ayinde et al. incorporated a total of 20 studies in the meta-analysis and 29 studies in the systematic review. For assessing injection pain, a standardized mean difference with a 95% confidence interval (CI) was stated. Out of all, 13 intramuscular injection techniques were identified and in 10 studies, local pressure was applied to the injection site.

Of these, the application of manual pressure and rhythmic tapping to the injection site minimized injection pain. On the other hand, the usage of a plastic device for applying local pressure to the skin (ShotBlocker) didn't considerably lower pain. The technique of acupressure involved the application of sustained pressure.

This was subsequently followed by tapping (application of intermittent pressure) to the acupressure points local to the site of injection. It was reported to diminish pain, as did injections to the ventrogluteal site in comparison with the dorsogluteal site. No sufficient evidence was found on the advantages of cold needle and  Z track technique on injection pain. 

Following drawing up the injectate, the impact of altering the needle on injection-linked pain was found to be conflicting. Moreover, warming the injectate was not found to lower pain.  Thus, applying local pressure, specifically manual pressure and rhythmic tapping on the site of injection seems to be valuable in diminishing intramuscular injection pain.