Exploring the Application of a First Metatarsophalangeal Joint Isometric Flexion Test in Pre-Professional Ballet Dancers / Ann-Marie Brennan (2025)

Background: Foot and ankle injuries account for 39% of ballet injuries, with pointe work responsible for 71.1% of injuries requiring medical attention. Current screening protocols lack assessment of first metatarsophalangeal joint flexion (1MTPJ-F) strength, critical for ballet-specific toe flexor control during demi-pointe and en pointe positions. Objectives: To (1) describe gender-stratified reference values for 1MTPJ-F strength in pre-professional ballet (2) examine whether Single Leg Standing Plantar Flexion (SLS-PF) strength predicts 1MTPJ-F strength using linear mixed-effects modeling, informing the need for potential additional assessment protocols. Methods: Cross-sectional study of 107 pre-professional ballet dancers (58 females, 49 males; ages 11-16 years). 107 participants completed 1MTPJ-F testing (ForceFrame System) and 87 participants completed SLS-PF testing (ForceDecks). All measurements were normalised to body weight. Data analysis included descriptive statistics, and a linear mixed-effects regression was used to model 1MTPJ-F strength as a function of SLS-PF performance, gender, and limb side, with random intercepts for participants. Results: Preliminary reference values were presented for females (0.45-0.48 xBW) and males (0.46-0.50 xBW), with minimal gender differences. The model explained 85% of variance, with only limb side significant (β = 0.58, p < .001), indicating right-side dominance. SLS-PF performance showed a positive trend but was not statistically significant (β = 0.15, p = .13). Gender was not a significant predictor (β = 0.11, p = .28). Conclusions: This study presents preliminary descriptive benchmarks for 1MTPJ-F strength in ballet dancers. SLS-PF testing did not predict 1MTPJ-F strength, demonstrating that the calf-dominant assessment inadequately predicts toe flexor capacity. Results support incorporating specific 1MTPJ-F testing in dancer assessment protocols, with future studies requiring forefoot length normalisation to distinguish muscle strength from anatomical leverage effects. Keywords: toe flexor muscle strength, intrinsic foot muscles, extrinsic foot muscles, physical screening, limb asymmetries Background: Foot and ankle injuries account for 39% of ballet injuries, with pointe work responsible for 71.1% of injuries requiring medical attention. Current screening protocols lack assessment of first metatarsophalangeal joint flexion (1MTPJ-F) strength, critical for ballet-specific toe flexor control during demi-pointe and en pointe positions. Objectives: To (1) describe gender-stratified reference values for 1MTPJ-F strength in pre-professional ballet (2) examine whether Single Leg Standing Plantar Flexion (SLS-PF) strength predicts 1MTPJ-F strength using linear mixed-effects modeling, informing the need for potential additional assessment protocols. Methods: Cross-sectional study of 107 pre-professional ballet dancers (58 females, 49 males; ages 11-16 years). 107 participants completed 1MTPJ-F testing (ForceFrame System) and 87 participants completed SLS-PF testing (ForceDecks). All measurements were normalised to body weight. Data analysis included descriptive statistics, and a linear mixed-effects regression was used to model 1MTPJ-F strength as a function of SLS-PF performance, gender, and limb side, with random intercepts for participants. Results: Preliminary reference values were presented for females (0.45-0.48 xBW) and males (0.46-0.50 xBW), with minimal gender differences. The model explained 85% of variance, with only limb side significant (β = 0.58, p < .001), indicating right-side dominance. SLS-PF performance showed a positive trend but was not statistically significant (β = 0.15, p = .13). Gender was not a significant predictor (β = 0.11, p = .28). Conclusions: This study presents preliminary descriptive benchmarks for 1MTPJ-F strength in ballet dancers. SLS-PF testing did not predict 1MTPJ-F strength, demonstrating that the calf-dominant assessment inadequately predicts toe flexor capacity. Results support incorporating specific 1MTPJ-F testing in dancer assessment protocols, with future studies requiring forefoot length normalisation to distinguish muscle strength from anatomical leverage effects. Keywords: toe flexor muscle strength, intrinsic foot muscles, extrinsic foot muscles, physical screening, limb asymmetries