Participants were shown photographs given instructions and given time to

Participants were shown photographs given

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Participants were shown photographs, given instructions, and given time to practice each pinch grip type. In each trial, the plunger was pressed maximally for 5 seconds. Verbal encour-agement was given during the trials to help pro-mote maximal exertion. A one-minute rest was given between trials with additional rest pro-vided if the participant reported symptoms of fatigue. Each grip was performed twice, and the peak force was recorded. A third trial was per-formed if the first two trials differed by more than 15%. Conditions were blocked by grip span (wide or narrow), alternating the starting grip span between each participant. Both hand and pinch grip type order were randomized. Thus, each pinch grip was used with both dominant and nondominant hands in both wide (8.3 cm) TABLE 1:Participant Characteristics and Anthropometric Measures (n= 20)VariableMeanStandard DeviationRangeAge (years)351122–56Weight (kg)70.815.852.6–117.4Height (cm)1676.0153–177Hand breadth (cm)–8.6Thumb length (cm)–6.3Palm length (cm)–11.0Finger length (cm)–8.0Hand length (cm)17.30.816.0–18.5
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1090 November 2017 - Human Factorsand narrow (2.5 cm) grip spans to simulate full and near empty syringe conditions. A tripod-mounted digital camera recorded hand and wrist posture during each trial.Data AnalysisFor each of the three one-handed postures, the mean peak force of all participants was evaluated using a 2 (grip span) × 2 (hand) × 3 (pinch grip type) repeated measures ANOVA (SPSS v 17.0; IBM Corporation, Armonk, NY, USA). To include the two-handed pinch grip, a 2 (grip span) × 4 (pinch grip type) repeated measures ANOVA was performed including the mean peak force between dominant and nondominant hands. Significant effects were followed up using Tukey’s honest significant difference (HSD) test. To examine the rela-tionships between strength and anthropometric measures, Pearson product moment correlations were performed. An α level of 0.05 was used for all tests.RESULTSThere were significant main effects for all variables in the one-handed grips (grip, span, and hand). The dominant hand was significantly stronger than the nondominant hand, and the narrow grip was significantly stronger than the wide grip. The thenar grip was stronger than the chuck pinch, which was stronger than the variation of the chuck pinch (p< .05) (Table 2). The two-handed pinch was significantly stron-ger than the chuck and chuck variation pinches but not the thenar pinch (p< .05). The mean maximum forces may be found in Table 2.A three-way interaction between Pinch Grip Type × Hand × Grip Span was found for pinch force, F(2, 38) = 4.7, p< .01 (Figure 2). This was primarily due to a greater maximum force in the wide (111.1 ± 19.2 N) versus the narrow (102.2 ± 22.6 N) dominant hand thenar grip while there was no difference in the nondomi-nant hand (wide, 100.9 ± 21.7 N; narrow, 100.2 ± 27.5 N). All other grip types had greater forces Figure 1.Pinch grip types with a (left) narrow and (right) wide grip span. (A) Chuck pinch. (B) Chuck pinch variation. (C) Thenar pinch. (D) Two-handed pinch.
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GRIPTYPEINSYRINGEUSE1091in the narrow grip or no significant difference (Figure 2). Thenar grip force was significantly greater than both the chuck and chuck variation grips for both hands and both grip spans. In the
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  • Fall '07
  • Statistical significance, Median nerve, Hand strength, pinch grip

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