Maximal isometric force is more strongly associated with Achilles tendinopathy severity than rate of force development and muscle force steadiness

Vallance, Patrick; Crowley, Liam; Hasani, Fatmah; Malliaras, Peter

doi:10.1016/j.jsams.2019.08.154

Cited by 2 publications

(3 citation statements)

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“…Based on our findings, the ability of the triceps surae in controlling torque during submaximal contractions is not affected in runners with AT, which aligns with another study (Vallance et al 2019 ). Torque steadiness is affected by pain (Rice et al 2015 ), and lower torque steadiness has been reported in other chronic (Rice et al 2015 ) and painful musculoskeletal conditions (Martinez-Valdes et al 2019 ; Telianidis et al 2014 ).…”

Section: Discussionsupporting

confidence: 93%

Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study

et al. 2022

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Objectives Deficits in muscle performance could be a consequence of a reduced ability of a motor neuron to increase the rate in which it discharges. This study aimed to investigate motor unit (MU) discharge properties of each triceps surae muscle (TS) and TS torque steadiness during submaximal intensities in runners with Achilles tendinopathy (AT). Methods We recruited runners with ( n = 12) and without ( n = 13) mid-portion AT. MU discharge rate was analysed for each of the TS muscles, using high-density surface electromyography during 10 and 20% isometric plantar flexor contractions. Results MU mean discharge rate was lower in the gastrocnemius lateralis (GL) in AT compared to controls. In AT, GL MU mean discharge rate did not increase as torque increased from 10% peak torque, 8.24 pps (95% CI 7.08 to 9.41) to 20%, 8.52 pps (7.41 to 9.63, p = 0.540); however, in controls, MU discharge rate increased as torque increased from 10%, 8.39 pps (7.25–9.53) to 20%, 10.07 pps (8.89–11.25, p < 0.001). There were no between-group difference in gastrocnemius medialis (GM) or soleus (SOL) MU discharge rates. We found no between-group differences in coefficient of variation of MU discharge rate in any of the TS muscles nor in TS torque steadiness. Conclusion Our data demonstrate that runners with AT may have a lower neural drive to GL, failing to increase MU discharge rate to adjust for the increase in torque demand. Further research is needed to understand how interventions focussing on increasing neural drive to GL would affect muscle function in runners with AT. Supplementary Information The online version contains supplementary material available at 10.1007/s00421-022-05089-w.

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Section: Discussionsupporting

confidence: 93%

Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Based on our findings, the ability of the triceps surae in controlling torque during submaximal contractions is not affected in runners with AT, which aligns with another study 31 . Torque steadiness is affected by pain 18 , and reduced torque steadiness has been reported in other chronic 18 and painful musculoskeletal conditions 15,20 .…”

Section: Discussionsupporting

confidence: 92%

“…Based on our findings, the ability of the triceps surae in controlling torque during submaximal contractions is not affected in runners with AT, which aligns with another study 31 .…”

Section: Coefficient Of Variation Of Motor Unit Discharge Rate and To...supporting

confidence: 92%

Reduced motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy

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Orssatto

Sakugawa

et al. 2022

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ObjectivesDeficits in muscle performance could be a consequence of a reduced ability of a motor neuron to increase the rate in which it discharges. This study aimed to investigate motor unit (MU) discharge properties of each Triceps surae muscle (TS), and TS torque steadiness during submaximal intensities in runners with Achilles tendinopathy (AT).MethodsWe recruited runners with (n=12) and without (n=13) mid-portion AT. MU discharge rate was analysed for each of the TS muscles, using High-Density surface electromyography during 10 and 20% isometric plantar flexor contractions.ResultsMU mean discharge rate was lower in the Gastrocnemius lateralis (GL) in AT compared to controls. In AT, GL MU mean discharge rate did not increase as torque increased from 10% peak torque, 8.24pps (95%CI: 7.08 to 9.41) to 20%, 8.52pps (7.41 to 9.63, p=0.540); however, in controls, MU discharge rate increased as torque increased from 10%, 8.39pps (7.25 to 9.53) to 20%, 10.07pps (8.89 to 11.25, p<0.001). There were no between-group difference in Gastrocnemius medialis (GM) or Soleus (SOL) MU discharge rates. We found no between-groups differences in coefficient of variation of MU discharge rate in any of the TS muscles nor in TS torque steadiness.ConclusionOur data demonstrates that runners with AT may have a reduced neural drive to GL, failing to increase MU discharge rate to adjust for the increase in torque demand. Further research is needed to understand how interventions focusing on increasing neural drive to GL would affect muscle function in runners with AT.

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Maximal isometric force is more strongly associated with Achilles tendinopathy severity than rate of force development and muscle force steadiness

Cited by 2 publications

References 0 publications

Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study

Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study

Reduced motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy

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