Plantar Loading Characteristics During Walking in Females With and Without Patellofemoral Pain

2015 ◽  
Vol 105 (1) ◽  
pp. 1-7 ◽  
Author(s):  
John D. Willson ◽  
Eric D. Ellis ◽  
Thomas W. Kernozek
Keyword(s):  
Contact Area ◽  
Patellofemoral Pain ◽  
Peak Force ◽  
First Metatarsal ◽  
Time Integral ◽  
Foot Pronation ◽  
Force Time ◽  
Arch Index ◽  
Plane Joint ◽  
Force Time Integral

Background Patellofemoral pain (PFP) is a common injury, particularly in females. Foot pronation may promote knee and hip transverse plane joint kinematics during gait thought to contribute to PFP. Greater knowledge of plantar loading characteristics in females with PFP may be valuable to provide a basis for clinical decisions regarding footwear and foot orthoses. The purpose of this study was to compare plantar loading distribution in females with and without PFP during gait. Methods Plantar pressure during walking was recorded from 19 females with PFP and 20 females without PFP. Contact area, peak force, and force-time integral were evaluated in ten plantar areas. Arch index was also calculated from contact area data during gait. Results Contact area in females with PFP was 9% smaller in the first metatarsal region (P = .039) and 20% smaller in the midfoot region (P = .042) than in females without PFP. Peak force was 31% lower in the midfoot region for females with PFP (P = .027) and 13% lower in the first metatarsal region (P = .064). Force-time integral was 18% lower in the first metatarsal region in females with PFP (P = .024). Females with PFP demonstrated a lower arch index (suggesting a higher arch) (P = .028). Conclusions Decreased medial forefoot loading and decreased midfoot contact suggest decreased foot pronation during gait in females with PFP relative to females without PFP. Decreased foot pronation may foster increased patellofemoral joint loading rates. These data contribute to rationale for footwear modifications to modify plantar loading characteristics in people experiencing PFP.

scholarly journals Stimulation Pattern That Maximizes Force in Paralyzed and Control Whole Thenar Muscles

2002 ◽  
Vol 87 (5) ◽  
pp. 2271-2278 ◽  
Author(s):  
Lisa Griffin ◽  
Sharlene Godfrey ◽  
Christine K. Thomas
Keyword(s):  
Short Interval ◽  
Motor Units ◽  
Muscle Stiffness ◽  
Peak Force ◽  
Single Motor Units ◽  
Time Integral ◽  
Cord Injury ◽  
Force Time ◽  
And Control ◽  
Force Time Integral

The pattern of seven pulses that elicited maximal thenar force was determined for control muscles and those that have been paralyzed chronically by spinal cord injury. For each subject group ( n = 6), the peak force evoked by two pulses occurred at a short interval (5–15 ms; a “doublet”), but higher mean relative forces were achieved in paralyzed versus control muscles (41.4 ± 3.9% vs. 22.7 ± 2.0% maximal). Thereafter, longer intervals evoked peak force in each type of muscle (mean: 35 ± 1 ms, 36 ± 2 ms, respectively). With seven pulses, paralyzed and control muscles reached 76.4 ± 5.6% and 57.0 ± 2.6% maximal force, respectively. These force differences resulted from significantly greater doublet/twitch and doublet/tetanic force ratios in paralyzed (2.73 ± 0.08, 0.35 ± 0.03) compared with control muscles (2.07 ± 0.07, 0.25 ± 0.01). The greater force enhancement produced in paralyzed muscles with two closely spaced pulses may relate to changes in muscle stiffness and calcium metabolism. Peak force-time integrals were also achieved with an initial short interpulse interval, followed by longer intervals. The postdoublet intervals that produced peak force-time integrals in paralyzed and control muscles were longer than those for peak force, however (77 ± 3 ms, 95 ± 4 ms, respectively). These data show that the pulse patterns that maximize force and force-time integral in paralyzed muscles are similar to those that maximize these parameters in single motor units and various whole muscles across species. Thus the changes in neuromuscular properties that occur with chronic paralysis do not strongly influence the pulse pattern that optimizes muscle force or force-time integral.

scholarly journals Changes in Plantar Loading Based on Shoe Type and Sex During a Jump-Landing Task

2013 ◽  
Vol 48 (5) ◽  
pp. 601-609 ◽  
Author(s):  
Justin C. DeBiasio ◽  
Mary E. Russell ◽  
Robert J. Butler ◽  
James A. Nunley ◽  
Robin M. Queen
Keyword(s):  
Contact Area ◽  
Stress Fractures ◽  
Maximum Force ◽  
Lower Extremity Injury ◽  
Jump Landing ◽  
Time Integral ◽  
Running Shoes ◽  
History Of ◽  
Force Time ◽  
Force Time Integral

Context: Metatarsal stress fractures are common in cleated-sport athletes. Previous authors have shown that plantar loading varies with footwear, sex, and the athletic task. Objective: To examine the effects of shoe type and sex on plantar loading in the medial midfoot (MMF), lateral midfoot (LMF), medial forefoot (MFF), middle forefoot (MidFF), and lateral forefoot (LFF) during a jump-landing task. Design: Crossover study. Setting: Laboratory. Patients or Other Participants: Twenty-seven recreational athletes (14 men, 13 women) with no history of lower extremity injury in the last 6 months and no history of foot or ankle surgery. Main Outcome Measure(s): The athletes completed 7 jumping trials while wearing bladed-cleat, turf-cleat, and running shoes. Maximum force, contact area, contact time, and the force-time integral were analyzed in each foot region. We calculated 2 × 3 analyses of variance (α = .05) to identify shoe-condition and sex differences. Results: We found no shoe × sex interactions, but the MMF, LMF, MFF, and LFF force-time integrals were greater in men (P < .03). The MMF maximum force was less with the bladed-cleat shoes (P = .02). Total foot and MidFF maximum force was less with the running shoes (P < .01). The MFF and LFF maximum forces were different among all shoe conditions (P < .01). Total foot contact area was less in the bladed-cleat shoes (P = .01). The MMF contact area was greatest in the running shoes (P < .01). The LFF contact area was less in the running shoes (P = .03). The MFF and LFF force-time integrals were greater with the bladed-cleat shoes (P < .01). The MidFF force-time integral was less in the running shoes (P < .01). Conclusions: Independent of shoe, men and women loaded the foot differently during a jump landing. The bladed cleat increased forefoot loading, which may increase the risk for forefoot injury. The type of shoe should be considered when choosing footwear for athletes returning to activity after metatarsal stress fractures.

scholarly journals Foot Posture and Plantar Loading With Ankle Bracing

2021 ◽  
Vol 56 (5) ◽  
pp. 461-472
Author(s):  
Laura C. Dickerson ◽  
Robin M. Queen
Keyword(s):  
Contact Area ◽  
Repeated Measures ◽  
Center Of Pressure ◽  
Maximum Force ◽  
Medial Side ◽  
Time Integral ◽  
Foot Posture ◽  
Force Time ◽  
Force Time Integral ◽  
Ankle Bracing

Context Arch height is one important aspect of foot posture. An estimated 20% of the population has pes planus and 20% has pes cavus. These abnormal foot postures can alter lower extremity kinematics and plantar loading and contribute to injury risk. Ankle bracing is commonly used in sport to prevent these injuries, but no researchers have examined the effects of ankle bracing on plantar loading. Objective To evaluate the effects of ankle braces on plantar loading during athletic tasks. Design Cross-sectional study. Setting Laboratory. Patients or Other Participants A total of 36 participants (11 men, 25 women; age = 23.1 ± 2.5 years, height = 1.72 ± 0.09 m, mass = 66.3 ± 14.7 kg) were recruited for this study. Intervention(s) Participants completed walking, running, and cutting tasks in 3 bracing conditions: no brace, lace-up ankle-support brace, and semirigid brace. Main Outcome Measure(s) We analyzed the plantar-loading variables of contact area, maximum force, and force-time integral for 2 midfoot and 3 forefoot regions and assessed the displacement of the center of pressure. A 3 × 3 mixed-model repeated-measures analysis of variance was used to determine the effects of brace and foot type (α = .05). Results Foot type affected force measures in the middle (P range = .003–.047) and the medial side of the foot (P range = .004–.04) in all tasks. Brace type affected contact area in the medial midfoot during walking (P = .005) and cutting (P = .01) tasks, maximum force in the medial and lateral midfoot during all tasks (P < .001), and force-time integral in the medial midfoot during all tasks (P < .001). Portions of the center-of-pressure displacement were affected by brace wear in both the medial-lateral and anterior-posterior directions (P range = .001–.049). Conclusions Ankle braces can be worn to redistribute plantar loading. Additional research should be done to evaluate their effectiveness in injury prevention.

scholarly journals Plantar Loading During Cutting While Wearing a Rigid Carbon Fiber Insert

2014 ◽  
Vol 49 (3) ◽  
pp. 297-303 ◽  
Author(s):  
Robin M. Queen ◽  
Alicia N. Abbey ◽  
Ravi Verma ◽  
Robert J. Butler ◽  
James A. Nunley
Keyword(s):  
Contact Area ◽  
Peak Pressure ◽  
Pressure Profile ◽  
Delayed Union ◽  
Stress Fractures ◽  
Lower Extremity Injury ◽  
Time Integral ◽  
Carbon Plate ◽  
Force Time ◽  
Force Time Integral

ContextStress fractures are one of the most common injuries in sports, accounting for approximately 10% of all overuse injuries. Treatment of fifth metatarsal stress fractures involves both surgical and nonsurgical interventions. Fifth metatarsal stress fractures are difficult to treat because of the risks of delayed union, nonunion, and recurrent injuries. Most of these injuries occur during agility tasks, such as those performed in soccer, basketball, and lacrosse.Objective:To examine the effect of a rigid carbon graphite footplate on plantar loading during 2 agility tasks.Design: Crossover study.Setting:Laboratory.Patients or Other Participants:A total of 19 recreational male athletes with no history of lower extremity injury in the past 6 months and no previous metatarsal stress fractures were tested.Main Outcome Measure(s): Seven 45° side-cut and crossover-cut tasks were completed in a shoe with or without a full-length rigid carbon plate. Testing order between the shoe conditions and the 2 cutting tasks was randomized. Plantar-loading data were recorded using instrumented insoles. Peak pressure, maximum force, force-time integral, and contact area beneath the total foot, the medial and lateral midfoot, and the medial, middle, and lateral forefoot were analyzed. A series of paired t tests was used to examine differences between the footwear conditions (carbon graphite footplate, shod) for both cutting tasks independently (α = .05).Results:During the side-cut task, the footplate increased total foot and lateral midfoot peak pressures while decreasing contact area and lateral midfoot force-time integral. During the crossover-cut task, the footplate increased total foot and lateral midfoot peak pressure and lateral forefoot force-time integral while decreasing total and lateral forefoot contact area.Conclusions:Although a rigid carbon graphite footplate altered some aspects of the plantar-pressure profile during cutting in uninjured participants, it was ineffective in reducing plantar loading beneath the fifth metatarsal.

scholarly journals Progressive recruitment of muscle fibers is not necessary for the slow component of V̇o2 kinetics

2008 ◽  
Vol 105 (2) ◽  
pp. 575-580 ◽  
Author(s):  
Jerzy A. Zoladz ◽  
L. Bruce Gladden ◽  
Michael C. Hogan ◽  
Zenon Nieckarz ◽  
Bruno Grassi
Keyword(s):  
Slow Component ◽  
Muscle Fibers ◽  
Constant Load ◽  
Peak Force ◽  
Time Integral ◽  
V̇o2 Kinetics ◽  
Force Time ◽  
Kinetics Of ◽  
Force Time Integral

The “slow component” of O2 uptake (V̇o2) kinetics during constant-load heavy-intensity exercise is traditionally thought to derive from a progressive recruitment of muscle fibers. In this study, which represents a reanalysis of data taken from a previous study by our group (Grassi B, Hogan MC, Greenhaff PL, Hamann JJ, Kelley KM, Aschenbach WG, Constantin-Teodosiu D, Gladden LB. J Physiol 538: 195–207, 2002) we evaluated the presence of a slow component-like response in the isolated dog gastrocnemius in situ ( n = 6) during 4 min of contractions at ∼60–70% of peak V̇o2. In this preparation all muscle fibers are maximally activated by electrical stimulation from the beginning of the contraction period, and no progressive recruitment of fibers is possible. Muscle V̇o2 was calculated as blood flow multiplied by arteriovenous O2 content difference. The muscle fatigued (force decreased by ∼20–25%) during contractions. Kinetics of adjustment were evaluated for 1) V̇o2, uncorrected for force development; 2) V̇o2 normalized for peak force; 3) V̇o2 normalized for force-time integral. A slow component-like response, described in only one muscle out of six when uncorrected V̇o2 was considered, was observed in all muscles when V̇o2/peak force and V̇o2/force-time were considered. The amplitude of the slow component-like response, expressed as a fraction of the total response, was higher for V̇o2/peak force (0.18 ± 0.06, means ± SE) and for V̇o2/force-time (0.22 ± 0.05) compared with uncorrected V̇o2 (0.04 ± 0.04). A progressive recruitment of muscle fibers may not be necessary for the development of the slow component of V̇o2 kinetics, which may be caused by the metabolic factors that induce muscle fatigue and, as a consequence, reduce the efficiency of muscle contractions.

Skeletal Muscle Specific Calpastatin Overexpression Mitigates Muscle Weakness in Aging and Extends Lifespan

2021 ◽  
Author(s):  
Elizabeth A. Schroder ◽  
Lin Wang ◽  
Yuan Wen ◽  
Leigh Ann P. Callahan ◽  
Gerald S. Supinski
Keyword(s):  
Skeletal Muscle ◽  
Peak Force ◽  
Force Frequency ◽  
Time Integral ◽  
Potential Contributor ◽  
Force Time ◽  
Aging Muscle ◽  
And Function ◽  
The Impact ◽  
Force Time Integral

Calpain activation has been postulated as a potential contributor to the loss of muscle mass and function associated with both aging and disease but limitations of previous experimental approaches have failed to completely examine this issue. We hypothesized that mice overexpressing calpastatin, an endogenous inhibitor of calpain (CalpOX), solely in skeletal muscle would show an amelioration of the aging muscle phenotype. We assessed 4 groups of mice (age in months): (1) young wild type (5.71±0.43) (WT); (2) young CalpOX (5.6±0.5); (3) old WT (25.81±0.56); and (4) old CalpOX (25.91±0.60) for diaphragm and limb muscle (extensor digitorum longus, EDL) force frequency relations. Aging significantly reduced diaphragm and EDL peak force in old WT mice, and decreased the force-time integral during a fatiguing protocol by 48% and 23% in aged WT diaphragm and EDL, respectively. In contrast, we found that CalpOX mice had significantly increased diaphragm and EDL peak force in old mice, similar to that observed in young mice. The impact of aging on the force-time integral during a fatiguing protocol was abolished in the diaphragm and EDL of old CalpOX animals. Surprisingly, we found that CalpOX had a significant impact on longevity, increasing median survival from 20.55 months in WT mice to 24 months in CalpOX mice (p = 0.0006).

scholarly journals Force-time integral decreases with ejection despite constant oxygen consumption and pressure-volume area in dog left ventricle.

1987 ◽  
Vol 60 (6) ◽  
pp. 797-803 ◽  
Author(s):  
H Suga ◽  
Y Goto ◽  
T Nozawa ◽  
Y Yasumura ◽  
S Futaki ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Left Ventricle ◽  
Time Integral ◽  
Force Time ◽  
Force Time Integral

The Effect of Muscle Lentgh on Force-Time Integral in Relation to Energy-Rich Phosphate Consumption

1985 ◽  
pp. 605-610 ◽  
Author(s):  
A. De Haan ◽  
J. E. Van Doorn ◽  
P. A. Huijing ◽  
R. D. Woittiez ◽  
H. G. Westra
Keyword(s):  
Time Integral ◽  
Force Time ◽  
Force Time Integral

Regulation of energy consumption in cardiac muscle: analysis of isometric contractions

1999 ◽  
Vol 276 (3) ◽  
pp. H998-H1011 ◽  
Author(s):  
Amir Landesberg ◽  
Samuel Sideman
Keyword(s):  
Energy Consumption ◽  
Cardiac Muscle ◽  
Feedback Mechanism ◽  
Isometric Contractions ◽  
Cross Bridge ◽  
Time Integral ◽  
Length Relationship ◽  
Cross Bridges ◽  
Force Time ◽  
Force Time Integral

The well-known linear relationship between oxygen consumption and force-length area or the force-time integral is analyzed here for isometric contractions. The analysis, which is based on a biochemical model that couples calcium kinetics with cross-bridge cycling, indicates that the change in the number of force-generating cross bridges with the change in the sarcomere length depends on the force generated by the cross bridges. This positive-feedback phenomenon is consistent with our reported cooperativity mechanism, whereby the affinity of the troponin for calcium and, hence, cross-bridge recruitment depends on the number of force-generating cross bridges. Moreover, it is demonstrated that a model that does not include a feedback mechanism cannot describe the dependence of energy consumption on the loading conditions. The cooperativity mechanism, which has been shown to determine the force-length relationship and the related Frank-Starling law, is shown here to provide the basis for the regulation of energy consumption in the cardiac muscle.

Preload does not influence nonmechanical O2 consumption in isolated rabbit heart

1994 ◽  
Vol 266 (3) ◽  
pp. H1047-H1054 ◽  
Author(s):  
A. Higashiyama ◽  
M. W. Watkins ◽  
Z. Chen ◽  
M. M. LeWinter
Keyword(s):  
Energy Consumption ◽  
Diastolic Pressure ◽  
Rabbit Heart ◽  
Left Ventricular ◽  
Energetic Cost ◽  
O2 Consumption ◽  
Time Integral ◽  
Force Time ◽  
Whole Heart ◽  
Force Time Integral

Myocardial energy consumption for nonmechanical activity (excitation-contraction coupling) has been shown to be length dependent in isolated muscle studies but no more than minimally affected by preload in the whole heart. However, unloaded O2 consumption (VO2, which is used to estimate nonmechanical VO2 in whole heart) may not be accurate for quantifying nonmechanical energy consumption, because it contains VO2 for residual cross-bridge cycling. To more accurately determine the influence of left ventricular (LV) diastolic volume on nonmechanical VO2 in whole heart, we employed a new method for quantifying nonmechanical VO2, using the drug 2,3-butanedione monoxime (BDM). We measured VO2 and force-time integral during infusion of BDM (< or = 5 mM) at high (VH) and low LV volumes (VL) in 16 excised isovolumically contracting red blood cell-perfused rabbit ventricles. LV end-diastolic pressure was 9.7 +/- 4.6 and 3.8 +/- 2.8 (SD) mmHg at VH and VL, respectively. Nonmechanical VO2, estimated as the VO2-axis intercept of the linear VO2-force-time integral relation obtained during BDM infusion, did not differ significantly between VH and VL (0.0137 +/- 0.0083 and 0.0132 +/- 0.0090 ml O2.beat-1 x 100 gLV-1, P = 0.702). A multiple linear regression analysis for the pooled data confirmed this finding (P = 0.361). We conclude that, in the rabbit heart, LV diastolic volume does not importantly affect nonmechanical energy consumption over a physiological range of LV end-diastolic pressure. This indicates that length-dependent activation does not have an energetic cost in whole rabbit heart and suggests that its predominant mechanism is increased Ca2+ affinity for the contractile proteins.

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