Grip Type Alters Maximal Pinch Forces in Syringe Use

Objective: The purpose of this study was to determine maximum forces during syringe use for different grips found in the field. Background: Prolonged syringe use in chemotherapy drug delivery is associated with pain and injury in nurses and technicians. Method: Twenty healthy female hospital workers generated isometric maximum voluntary force using a 30 cc syringe with four pinch grips (chuck, chuck variation, thenar, two-handed). Both dominant and nondominant hands were used with the syringe plunger fixed in wide (8.3 cm) and narrow (2.5 cm) grip spans. Participants were encouraged to position the apparatus in the most comfortable position and exert a maximal effort for 5 seconds. Results: Significant interaction effects were found: Grip Span × Pinch Type, Hand × Pinch Type, and Grip Span × Hand × Pinch Type (p < .05). The results demonstrated that the thenar (103.6 ± 22.9 N) and two-handed (104.7 ± 17.1 N) pinches produced the highest forces. Conclusion: Thenar and two-handed pinch grips may be the preferred pinch type to lower the relative efforts required to use a syringe and may be one strategy to assist with reduction of musculoskeletal disorder risk associated with syringe use. Application: Determining maximal syringe press forces allows workers and ergonomists to develop better strategies for managing the cumulative loads during drug delivery and mixing.