The influence of patellar tendon and muscle-tendon unit stiffness on quadriceps explosive strength in man

TY - JOUR

T1 - The influence of patellar tendon and muscle-tendon unit stiffness on quadriceps explosive strength in man

AU - Massey, Garry

AU - Balshaw, Thomas

AU - Maden-wilkinson, Thomas M.

AU - Tillin, Neale

AU - Folland, Jonathan

PY - 2017/3/16

Y1 - 2017/3/16

N2 - The influence of musculotendinous tissue stiffness on contractile rate of torque development(RTD) remains opaque. This study examined the relationships between both patellar tendon(PT) and vastus lateralis (VL) muscle-tendon unit (MTU) stiffness, and voluntary and evokedknee extension RTD. Fifty-two healthy untrained males completed duplicate laboratory sessions.Absolute and relative RTD was measured at 50 Nm/25%MVT increments from onsetand sequentially during explosive voluntary and evoked octet (supramaximal stimulation: [8pulses at 300Hz]) isometric contractions. Isometric maximum voluntary torque (MVT) wasalso assessed. PT and MTU stiffness were derived from simultaneous force and ultrasoundrecordings of the PT and VL aponeurosis during constant RTD ramp contractions. Absoluteand relative (to MVT and resting tissue length) stiffness (k) was measured over identicaltorque increments as RTD. Pearson’s correlations tested relationships between stiffness andRTD measurements over matching absolute/relative torque increments. Absolute and relativePT k was unrelated to equivalent voluntary or evoked RTD (r=0.020.255, P=0.069-0.891).Absolute MTU k was unrelated to voluntary or evoked RTD (r≤0.191, P≥0.184), howeversome measures of relative MTU k were related to relative voluntary/evoked RTD (e.g.RTD25-50%MVT r=0.374/0.353, P=0.007/0.014). In conclusion, relative MTU k explained asmall proportion of the variance in relative voluntary and evoked RTD (both ≤19%), despiteno association of absolute MTU k or absolute/relative PT k with equivalent RTD measures.Therefore the muscle-aponeurosis component, but not free tendon was associated with relativeRTD, although it seems an overriding influence of MVT negated any relationship of absoluteMTU k and absolute RTD. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society. The attached document (embargoed until 16/03/2018) is an author produced version of a paper published in Experimental Physiology, uploaded in accordance with the publisher’s self- archiving policy. The final published version (version of record) is available online at http://onlinelibrary.wiley.com/doi/10.1113/EP086190/abstract. Some minor differences between this version and the final published version may remain. We suggest you refer to the final published version should you wish to cite from it.Funded by: Arthritis Research UK. Grant Number: 20194

AB - The influence of musculotendinous tissue stiffness on contractile rate of torque development(RTD) remains opaque. This study examined the relationships between both patellar tendon(PT) and vastus lateralis (VL) muscle-tendon unit (MTU) stiffness, and voluntary and evokedknee extension RTD. Fifty-two healthy untrained males completed duplicate laboratory sessions.Absolute and relative RTD was measured at 50 Nm/25%MVT increments from onsetand sequentially during explosive voluntary and evoked octet (supramaximal stimulation: [8pulses at 300Hz]) isometric contractions. Isometric maximum voluntary torque (MVT) wasalso assessed. PT and MTU stiffness were derived from simultaneous force and ultrasoundrecordings of the PT and VL aponeurosis during constant RTD ramp contractions. Absoluteand relative (to MVT and resting tissue length) stiffness (k) was measured over identicaltorque increments as RTD. Pearson’s correlations tested relationships between stiffness andRTD measurements over matching absolute/relative torque increments. Absolute and relativePT k was unrelated to equivalent voluntary or evoked RTD (r=0.020.255, P=0.069-0.891).Absolute MTU k was unrelated to voluntary or evoked RTD (r≤0.191, P≥0.184), howeversome measures of relative MTU k were related to relative voluntary/evoked RTD (e.g.RTD25-50%MVT r=0.374/0.353, P=0.007/0.014). In conclusion, relative MTU k explained asmall proportion of the variance in relative voluntary and evoked RTD (both ≤19%), despiteno association of absolute MTU k or absolute/relative PT k with equivalent RTD measures.Therefore the muscle-aponeurosis component, but not free tendon was associated with relativeRTD, although it seems an overriding influence of MVT negated any relationship of absoluteMTU k and absolute RTD. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society. The attached document (embargoed until 16/03/2018) is an author produced version of a paper published in Experimental Physiology, uploaded in accordance with the publisher’s self- archiving policy. The final published version (version of record) is available online at http://onlinelibrary.wiley.com/doi/10.1113/EP086190/abstract. Some minor differences between this version and the final published version may remain. We suggest you refer to the final published version should you wish to cite from it.Funded by: Arthritis Research UK. Grant Number: 20194

U2 - 10.1113/EP086190

DO - 10.1113/EP086190

M3 - Article

SN - 1469-445X

JO - EXPERIMENTAL PHYSIOLOGY

JF - EXPERIMENTAL PHYSIOLOGY

ER -