Relationship between Reactive Strength and Leg Stiffness at Submaximal Velocity: Effects of Age on Distance Runners

Background: Musculotendinous reactive strength is a key factor for the utilization of elastic energy in sporting activities such as running. AIM: To evaluate the relationship between musculotendinous reactive strength and lower-limb stiffness during running as well as to identify age-related differences in both variables. Methods: Fifty-nine amateur endurance runners performed three 20-cm drop jumps and a constant 3-min easy run on a motorized treadmill. Reactive strength index and dynamic lower-limb stiffness were calculated with a photoelectric cell system by jumping and running, respectively. Additionally, sit to stand difference in plantar arch height was assessed as a static lower-limb stiffness measure. The cluster analysis allows the comparison between younger and older runners. Results: No significant correlations were found between jumping reactive strength and running lower-limb stiffness. The younger group performed better at drop jumps (p = 0.023, ES = 0.82), whereas higher-but-no-significant results were found for reactive strength index and stiffness-related metrics. Conclusions: Musculotendinous vertical reactiveness may not be transferred to combined vertical and horizontal movements such as running.

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Modulation of Stretch-Shortening-Cycle Behavior With Eccentric Loading of Triceps Surae: A Possible Therapeutic Mechanism

Journal of Sport Rehabilitation ◽

10.1123/jsr.2015-0129 ◽

2017 ◽

Vol 26 (2) ◽

pp. 151-158 ◽

Cited By ~ 2

Author(s):

James R. Debenham ◽

William I. Gibson ◽

Mervyn J. Travers ◽

Amity C. Campbell ◽

Garry T. Allison

Keyword(s):

Outcome Measures ◽

Lower Limb ◽

Motor Performance ◽

Plantar Flexion ◽

Triceps Surae ◽

Temporal Muscle ◽

Ankle Kinematics ◽

Limb Stiffness ◽

Stretch Shortening Cycle ◽

Lower Limb Stiffness

Context:Eccentric exercises are increasingly being used to treat lower-limb musculoskeletal conditions such as Achilles tendinopathy. Despite widespread clinical application and documented efficacy, mechanisms underpinning clinical benefit remain unclear. Positive adaptations in motor performance are a potential mechanism.Objective:To investigate how an eccentric loading intervention influences measures of stretch-shortening-cycle (SSC) behavior during a hopping task.Design:Within-subjects repeated-measures observational study.Setting:University motion-analysis laboratory.Participants:Healthy adults.Interventions:A single intervention of 5 sets of 10 eccentric plantar-flexion contractions at 6 repetitions maximum using a commercial seated calf-raise machine.Main Outcome Measures:Lower-limb stiffness, sagittal-plane ankle kinematics, and temporal muscle activity of the agonist (soleus) and antagonist (tibialis anterior) muscles, measured during submaximal hopping on a custom-built sledge-jump system.Results:Eccentric loading altered ankle kinematics during submaximal hopping; peak angle shifted to a less dorsiflexed position by 2.9° and ankle angle precontact shifted by 4.4° (P < .001). Lower-limb stiffness increased from 5.9 to 6.8 N/m (P < .001), while surface EMG measures of soleus occurred 14–44% earlier (P < .001) after the loading intervention.Conclusions:These findings suggest that eccentric loading alters SSC behavior in a manner reflective of improved motor performance. Decreased ankle excursion, increased lower-limb stiffness, and alterations in motor control may represent a positive adaptive response to eccentric loading. These findings support the theory that mechanisms underpinning eccentric loading for tendinopathy may in part be due to improved “buffering” of the tendon by the neuromuscular system.

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Lower Limb Stiffness

Strength and Conditioning Journal ◽

10.1519/ssc.0b013e3182781b4e ◽

2012 ◽

Vol 34 (6) ◽

pp. 94-101 ◽

Cited By ~ 16

Author(s):

John J. McMahon ◽

Paul Comfort ◽

Stephen Pearson

Keyword(s):

Lower Limb ◽

Limb Stiffness ◽

Lower Limb Stiffness

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Prosthetic model, but not stiffness or height, affects the metabolic cost of running for athletes with unilateral transtibial amputations

Journal of Applied Physiology ◽

10.1152/japplphysiol.00896.2016 ◽

2017 ◽

Vol 123 (1) ◽

pp. 38-48 ◽

Cited By ~ 10

Author(s):

Owen N. Beck ◽

Paolo Taboga ◽

Alena M. Grabowski

Keyword(s):

Lower Limb ◽

Metabolic Cost ◽

Ground Reaction Forces ◽

Ground Contact ◽

Limb Stiffness ◽

Leg Stiffness ◽

In Series ◽

Reaction Forces ◽

Vertical Ground ◽

Vertical Ground Reaction Forces

Running-specific prostheses enable athletes with lower limb amputations to run by emulating the spring-like function of biological legs. Current prosthetic stiffness and height recommendations aim to mitigate kinematic asymmetries for athletes with unilateral transtibial amputations. However, it is unclear how different prosthetic configurations influence the biomechanics and metabolic cost of running. Consequently, we investigated how prosthetic model, stiffness, and height affect the biomechanics and metabolic cost of running. Ten athletes with unilateral transtibial amputations each performed 15 running trials at 2.5 or 3.0 m/s while we measured ground reaction forces and metabolic rates. Athletes ran using three different prosthetic models with five different stiffness category and height combinations per model. Use of an Ottobock 1E90 Sprinter prosthesis reduced metabolic cost by 4.3 and 3.4% compared with use of Freedom Innovations Catapult [fixed effect (β) = −0.177; P < 0.001] and Össur Flex-Run (β = −0.139; P = 0.002) prostheses, respectively. Neither prosthetic stiffness ( P ≥ 0.180) nor height ( P = 0.062) affected the metabolic cost of running. The metabolic cost of running was related to lower peak (β = 0.649; P = 0.001) and stance average (β = 0.772; P = 0.018) vertical ground reaction forces, prolonged ground contact times (β = −4.349; P = 0.012), and decreased leg stiffness (β = 0.071; P < 0.001) averaged from both legs. Metabolic cost was reduced with more symmetric peak vertical ground reaction forces (β = 0.007; P = 0.003) but was unrelated to stride kinematic symmetry ( P ≥ 0.636). Therefore, prosthetic recommendations based on symmetric stride kinematics do not necessarily minimize the metabolic cost of running. Instead, an optimal prosthetic model, which improves overall biomechanics, minimizes the metabolic cost of running for athletes with unilateral transtibial amputations.NEW & NOTEWORTHY The metabolic cost of running for athletes with unilateral transtibial amputations depends on prosthetic model and is associated with lower peak and stance average vertical ground reaction forces, longer contact times, and reduced leg stiffness. Metabolic cost is unrelated to prosthetic stiffness, height, and stride kinematic symmetry. Unlike nonamputees who decrease leg stiffness with increased in-series surface stiffness, biological limb stiffness for athletes with unilateral transtibial amputations is positively correlated with increased in-series (prosthetic) stiffness.

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Lower Limb Stiffness

Strength and Conditioning Journal ◽

10.1519/ssc.0b013e318268131f ◽

2012 ◽

Vol 34 (5) ◽

pp. 70-73 ◽

Cited By ~ 10

Author(s):

John James McMahon ◽

Paul Comfort ◽

Stephen Pearson

Keyword(s):

Lower Limb ◽

Limb Stiffness ◽

Lower Limb Stiffness

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A Simple Method for Measuring Lower Limb Stiffness During Running

Biomechanics of Training and Testing ◽

10.1007/978-3-319-05633-3_8 ◽

2018 ◽

pp. 165-193

Author(s):

Jean-Benoit Morin

Keyword(s):

Lower Limb ◽

Simple Method ◽

Limb Stiffness ◽

Lower Limb Stiffness

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Age Effect on Jumping Techniques and Lower Limb Stiffness During Vertical Jump

Research in Sports Medicine ◽

10.1080/15438620490497549 ◽

2004 ◽

Vol 12 (3) ◽

pp. 209-219 ◽

Cited By ~ 12

Author(s):

LI-I WANG ◽

DER-CHIA LIN ◽

CHENFU HUANG

Keyword(s):

Lower Limb ◽

Vertical Jump ◽

Age Effect ◽

Limb Stiffness ◽

Lower Limb Stiffness

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Lower limb stiffness testing in athletic performance: a critical review

Sports Biomechanics ◽

10.1080/14763141.2018.1460395 ◽

2018 ◽

pp. 1-22 ◽

Cited By ~ 6

Author(s):

Sean J. Maloney ◽

Iain M. Fletcher

Keyword(s):

Lower Limb ◽

Athletic Performance ◽

Critical Review ◽

Limb Stiffness ◽

Lower Limb Stiffness

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Relationship between Connective Tissue Morphology and Lower-Limb Stiffness in Endurance Runners. A Prospective Study

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18168453 ◽

2021 ◽

Vol 18 (16) ◽

pp. 8453

Author(s):

Alberto Rubio-Peirotén ◽

Felipe García-Pinillos ◽

Diego Jaén-Carrillo ◽

Antonio Cartón-Llorente ◽

Ferrán Abat ◽

...

Keyword(s):

Connective Tissue ◽

Lower Limb ◽

Time Trial ◽

Influential Factors ◽

Cross Sectional ◽

Positive Correlation ◽

Tissue Morphology ◽

Limb Stiffness ◽

The Relationship ◽

Lower Limb Stiffness

Background: The lower limb behaves like a spring compressing and decompressing during running, where lower-limb stiffness is one of the most influential factors. This prospective observational study is aimed at examining the relationship between the connective tissue morphology and lower-limb stiffness and investigating whether the barefoot/shod condition influences on such relationship. Methods: 14 male amateur runners (10-km time trial <50′) were included. Data were recorded over one session, where participants ran 2 trials (i.e., barefoot and shod conditions) of 3 minutes at 12 km/h, where running spatiotemporal parameters and vertical (Kvert) and leg stiffness (Kleg) were obtained. Prior to testing trials, thickness and cross-sectional area (CSA) were recorded for Achilles (AT) and patellar tendons (PT) and plantar fascia (PF) with ultrasound. Results: Under barefoot condition, a positive correlation was found between Kleg and AT-thickness and CSA and PF-thickness; and between Kvert and AT-thickness and PF thickness. Under shod condition, a positive correlation was found between Kleg and PT-CSA and PT-thickness, and between Kvert and PT-CSA and PT-thickness. Conclusions: The results reveal a specificity of the relationship between the lower-limb stiffness and the morphology of the connective tissue. Greater tendon shows higher lower-limb stiffness when that tendon is specially demanded by the function.

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