Force awakens: a new hope for athletic shoulder strength testing

• Published in: British journal of sports medicine 2019-05, Vol.53 (9), p.524-524
• Main Authors: Ashworth, Ben, Cohen, Daniel Dylan
• Format: Article
• Language: English
• Subjects: Asymmetry; Athletes; Coaches & managers; Knee; Rugby; Soccer; Sports injuries
• ISSN: 0306-3674; 1473-0480
• DOI: 10.1136/bjsports-2018-099457

[...]he is a risk for the weekend.’Table 1 Shoulder strength tests Post op Athletic shoulder test (T-position)* HHD† Grip strength Plyometric push-up‡ Net peak force§ (NPF) (N) RFD 0-100 ms† † (N/s) Prone ER (kg) Neutral grip (kg) Peak landing Left Right Left Right Left Right Left Right Total force (L+R) (N) Asymmetry Week 6 88.4 115.0 367 591 16.5 23.0 56.1 56.4 N/a¶ Week 10 121.2 118.9 445 580 21.0 21.3 57.4 63.5 1939 17% R** *Single force platform unilateral test—player lying prone with straight arm abducted to 90° (figure 2). †Hand-held dynamometry (make test) - Prone External Rotation (ER) at 90 degrees Abduction. ‡Dual force platform bilateral test. §Net peak force=total peak force—force at start of contraction. ¶N/a; not applicable—plyometric push-ups not performed until week 8 postop. **R=increased peak landing force on the right upper limb (17% higher than left in this example (bold values indicate true deficits). ††RFD 0-100 ms; average rate of force development over the first 100ms after the start of contraction - 23 % lower rate of force development in a T-position on the affected left shoulder (bold values). A conventional output variable such as peak force provides a blunt tool in comparison to more sensitive force production (rate) metrics that have implications around player capacity for explosive performance and joint protection.7 These lag behind peak force recovery during rehabilitation following lower body injury.7 Bilateral performance in the push-off phase of the PPU relates to tackling ability8 but assessing force symmetry in the landing phase could provide an indicator of the shoulder’s load acceptance capacity. Competing interests DDC is a shareholder in NMP technologies. who have commercialised the "ForceDecks" proprietary software used in data acquisition and analysis. Since the original submission of this editorial, BA now performs consultancy for Vald Performance.