T2 relaxation time measurements in tibiotalar cartilage after barefoot running and its relationship to ankle biomechanics

The influence of ankle kinematics and plantar pressure from mid-range barefoot running on T2 relaxation times of tibiotalar cartilage is unknown. This study aimed to quantitatively evaluate the T2 relaxation time of tibiotalar cartilage and ankle biomechanics following 5 km barefoot running. Twenty healthy runners (who had no 5 km barefoot running experience) underwent 3.0-Tesla magnetic resonance (MR) scans and assessment of running gait before and after 5 km barefoot running. Participants were divided into two groups consisting of marathon-experienced (n = 10) and novice (n = 10) with equal number of males and females in each group. Three musculoskeletal radiologists measured T2 relaxation times in 18 regions of the ankle cartilage: anterior zone, central zone, and posterior zone, or lateral, middle, and medial sections in the sagittal plane. Three-dimensional ankle kinetics, kinematics, and plantar pressure were all also assessed during barefoot running. In the novice group, the T2 relaxation time in the posterior zone of tibial cartilage (p = 0.001) and lateral section in both tibial (p = 0.02) and talar (p = 0.02) cartilage were significantly increased after barefoot running. Ankle kinematics exhibited significant changes in females. Plantar loading was shifted from the medial to lateral aspect after running. This included a significant reduction in the loading under the toes and the 1st, 2nd and 3rd metatarsals, with a significant increase under the 4th and 5th metatarsals and lateral midfoot. The results suggest that plantar pressure may directly lead to local increases in cartilage T2 signal, which was not associated with changes in ankle kinematics.     

Changes in the acid-base balance and lactate concentration in the blood in amateur ultramarathon runners during a 100-km run

The aim of this study was to analyse the acid-base balance and partial pressure of blood gases of participants during a 100-km run. Fourteen experienced amateur ultramarathon runners (age: 43.36±11.83 years; height: 175.29±6.98 cm; weight: 72.12±7.36 kg) completed the 100-km run. Blood samples were taken before the run; after 25, 50, 75, and 100 km; and 12 and 24 hours after the run. There were significant differences (p<0.05) between the mean values registered for acid-alkaline balance, buffering alkalies, and current bicarbonate in each segment of the run, especially during the third, fourth, and fifth segments of the run (i.e., between 50 and 100 km), and there were only significant differences associated with buffering alkalies and current bicarbonate during the recovery. However, all the changes were within the physiological norm. A significant decrease in the compressibility of oxygen was observed after 100 km (from 92.80±15.67 to 88.36±13.71 mmHg) and continued during the recovery to 75.06±8.60 mmHg 12 h after the run. Also there was a decrease in saturation to a mean value of 93.78±3.10 at 12 h after the run. Generally the amateurs runners are able to adjust their running speed so as not to provoke a significant acid-base imbalance or lactate acid accumulation.     

The compressive mechanical properties of diabetic and non-diabetic plantar soft tissue

Diabetic subjects are at an increased risk of developing plantar ulcers. Knowledge of the physiologic compressive properties of the plantar soft tissue is critical to understanding the possible mechanisms of ulcer formation and improving treatment options. The purpose of this study was to determine the compressive mechanical properties of the plantar soft tissue in both diabetic and non-diabetic specimens from six relevant locations beneath the foot, namely the hallux (big toe), first, third, and fifth metatarsal heads, lateral midfoot, and calcaneus (heel). Cylindrical specimens (1.905 cm diameter) from these locations were excised and separated from the skin and bone from 4 diabetic and 4 non-diabetic age-matched, elderly, fresh-frozen cadaveric feet. Specimens were then subjected to biomechanically realistic strains of ～50% in compression using triangle wave tests conducted at five frequencies ranging from 1 to 10 Hz to determine tissue modulus, energy loss, and strain rate dependence. Diabetic vs. non-diabetic results across all specimens, locations, and testing frequencies demonstrated altered mechanical properties with significantly increased modulus (1146.7 vs. 593.0 kPa) but no change in energy loss (68.5 vs. 67.9%). All tissue demonstrated strain rate dependence and tissue beneath the calcaneus was found to have decreased modulus and energy loss compared to other areas. The results of this study could be used to generate material properties for all areas of the plantar soft tissue in diabetic or non-diabetic feet, with implications for foot computational modeling efforts and potentially for pressure alleviating footwear that could reduce plantar ulcer incidence.     

Effects of dynamic stretching on energy cost and running endurance performance in trained male runners

The purpose of this study was to examine the effects of dynamic stretching on running energy cost and endurance performance in trained male runners. Fourteen male runners performed both a 30-minute preload run at 65% VO2max and a 30-minute time trial to assess running energy cost and performance, respectively. The subjects repeated both the trials after either 15 minutes of dynamic stretching (i.e., experimental condition) or quiet sitting (i.e., control condition) while the order was balanced between the subjects to avoid any order effect. The total calories expended were determined for the 30-minute preload run, whereas the distance covered was measured in the time trial. Average resting VO2 increased significantly (p < 0.05) after dynamic stretching (prestretch: 6.2 ± 1.7 vs. poststretch: 8.4 ± 2.1 ml·kg(-1)·min(-1)) but not during the quiet-sitting condition. Caloric expenditure was significantly higher during the 30-minute preload run for the stretching (416.3 ± 44.9 kcal) compared with that during the quiet sitting (399.3 ± 50.4 kcal) (p < 0.05). There was no difference in the distance covered after quiet sitting (6.3 ± 1.1 km) compared with that for the stretching condition (6.1 ± 1.3 km). These findings suggest that dynamic stretching does not affect running endurance performance in trained male runners.     

Effect of prefabricated thermoformable foot orthoses on plantar surface temperature after running: A gender comparison

There is a lack of evidence about the effect of different type of foot orthoses on plantar surface temperature. Moreover, that effect could be different depending on gender due to anatomical and physiological differences between men and women. The aim of the study was to analyze the effect of a prefabricated thermoformable foot orthosis on plantar surface temperature after running and taking gender differences into account. Thirty recreational runners (15 males, mean (standard deviation): 28 (7) years, 69.7 (6.5) kg, 1.74 (0.05) cm and 22.9 (1.7) kg/m²; and 15 females: 35 (7) years, 55.2 (6.9) kg, 1.63 (0.06) cm and 20.6 (1.9) kg/m²) carried out a maximum incremental test as pre-test, and two running tests on a treadmill at the laboratory wearing previously randomized different foot orthoses (thermoformable and prefabricated generic). The plantar surface temperature of the dominant foot sole in ten regions of interest was assessed before and immediately after 30-min running at 75% of VO_2max. The use of thermoformable foot orthoses produced lower temperatures only in men after the run in medial heel (P = 0.033, ES = 0.7), which then disappeared in temperature variation (after – before) (P = 0.910). Regarding gender, women showed lower temperatures before the run in both orthosis conditions (P < 0.039, ES > 0.8), but no differences in temperatures after the run (P = 0.910) in comparison with men. Moreover, absolute temperatures after running were always greater than before the run (P < 0.001, ES > 5.0). In conclusion, the thermoformable foot orthoses do not modify plantar surface temperature after running in healthy runners of either gender, compared to prefabricated generic foot orthoses. Although women present lower baseline plantar temperatures than men, these differences disappear after exercise.     

Creatine kinase isoenzyme activity during and after an ultra-distance (200 km) run

It is commonly assumed that creatine kinase (CK) activity in plasma is related to the state of an inflammatory response at 24-48 h, and also it has shown biphasic patterns after a marathon run. No information is available on CK isoenzymes after an ultra-marathon run. The purpose of the present study is to examine the CK isoenzymes after a 200 km ultra-marathon run and during the subsequent recovery. Blood samples were obtained during registration 1 2 h before the 200-km race and during the race at 100 km, 150 km and at the end of 200 km, as well as after a 24 h period of recovery. Thirty-two male ultra-distance runners participated in the study. Serum CPK showed a marked increase throughout the race and 24 h recovery period (p < 0.001). Serum CK during the race occurs mostly in the CK-MM isoform and only minutely in the CK-MB isoform and is unchanged in the CK-BB isoform. High-sensitivity C-reactive protein (hs-CRP), oestradiol, AST and ALT increased significantly from the pre-race value at 100 km and a further increase took place by the end of the 200 km run. The results of our study demonstrate a different release pattern of creatine kinase after an ultra-distance (200 km) run compared to the studies of marathon running and intense eccentric exercise, and changes in several biomarkers, indicative of muscle damage during the race, were much more pronounced during the latter half (100–200 km) of the race. However, the increases in plasma concentration of muscle enzymes may reflect not only structural damage, but also their rate of clearance.     

Physiological differences between black and white runners during a treadmill marathon

To determine why black distance runners currently out-perform white distance runners in South Africa, we measured maximum oxygen consumption (VO2max), maximum workload during a VO2max test (Lmax), ventilation threshold (VThr), running economy, inspiratory ventilation (VI), tidal volume (VT), breathing frequency (f) and respiratory exchange ratio (RER) in sub-elite black and white runners matched for best standard 42.2 km marathon times. During maximal treadmill testing, the black runners achieved a significantly lower (P less than 0.05) Lmax (17 km h-1, 2% grade, vs 17 km h-1, 4% grade) and VI max (6.21 vs 6.82 l kg-2/3 min-1), which was the result of a lower VT (101 vs 119 ml kg-2/3 breath-1) as fmax was the same in both groups. The lower VT in the black runners was probably due to their smaller body size. The VThr occurred at a higher percentage VO2max in black than in white runners (82.7%, SD 7.7% vs 75.6%, SD 6.2% respectively) but there were no differences in the VO2max. However, during a 42.2-km marathon run on a treadmill, the black athletes ran at the higher percentage VO2max (76%, SD 7.9% vs 68%, SD 5.3%), RER (0.96, SD 0.07 vs 0.91, SD 0.04) and f (56 breaths min-1, SD 11 vs 47 breaths min-1, SD 10), and at lower VT (78 ml kg-2/3 breath-1, SD 15 vs 85 ml kg-2/3 breath-1, SD 19). The combination of higher f and lower VT resulted in an identical VI.(ABSTRACT TRUNCATED AT 250 WORDS)     

The compressive material properties of the plantar soft tissue

The plantar soft tissue is the primary means of physical interaction between a person and the ground during locomotion. Dynamic loads greater than body weight are borne across the entire plantar surface during each step. However, most testing of these tissues has concentrated on the structural properties of the heel pad. The purpose of this study was to determine the material properties of the plantar soft tissue from six locations beneath: the great toe (subhallucal), the 1st, 3rd and 5th metatarsal heads (submetatarsal), the lateral midfoot (lateral submidfoot) and the heel (subcalcaneal). We obtained specimens from these locations from 11 young, non-diabetic donors; the tissue was cut into 2 cm x 2 cm blocks and the skin was removed. Stress relaxation experiments were conducted and the data were fit using the quasi-linear viscoelastic (QLV) theory. To determine tissue modulus, energy loss and the effect of test frequency, we also conducted displacement controlled triangle waves at five frequencies ranging from 0.005 to 10 Hz. The subcalcaneal tissue was found to have an increased relaxation time compared to the other areas. The subcalcaneal tissue was also found to have an increased modulus and decreased energy loss compared to the other areas. Across all areas, the modulus and energy loss increased for the 1 and 10 Hz tests compared to the other testing frequencies. This study is the first to generate material properties for all areas of the plantar soft tissue, demonstrating that the subcalcaneal tissue is different than the other plantar soft tissue areas. These data will have implications for foot computational modeling efforts and potentially for orthotic pressure reduction devices.     

Variations in running activity and enzymatic adaptations in voluntary running rats

The running behavior and biochemical markers of oxidative and glycolytic activities associated with voluntary running activity were studied in male Sprague-Dawley rats after 6 wk of training in exercise wheel cages. Twenty-four-hour recordings of running activity were used to quantify the number of individual running bouts, their duration and running speed, and the distance run per day. We then established three categories of voluntary running activity based on the mean distance run per day during the last 3 wk of training: low-activity runners averaged 2-5 km/day, medium runners 6-9 km/day, and high runners greater than 11 km/day. Each group demonstrated an intermittent, nocturnal running pattern, at relatively high intensities, with a similar mean running speed for all groups (avg approximately 45 m/min). Differences in total distance run per day were the result of variations in both the number and duration of individual running bouts. Specifically, high runners (n = 7) had 206 +/- 30 individual running bouts per 24 h, each lasting 87 +/- 7 s; medium runners (n = 7) 221 +/- 22 running bouts, lasting 47 +/- 5 s; and low runners (n = 7) 113 +/- 7 bouts, each lasting 40 +/- 7 s. Voluntary running depressed the rate of body weight gain compared with sedentary control rats, despite an increased food and water intake for all runners. Furthermore, drinking activity was temporally associated with running periods.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cholecystokinin, gastrin and stress hormone responses in marathon runners.

The purpose of this investigation was to determine the influence of long-distance running on the secretion of the gastrointestinal peptide hormones cholecystokinin (CCK) and gastrin. Several known stress hormones, ACTH, cortisol and norepinephrine, were also measured. The hormones were estimated before and after a competitive marathon run of 46.5 km and under control conditions a few weeks later. Except gastrin, all hormones were significantly higher under prerun conditions than under control conditions and were highest after the run. The most marked prerun elevation was in CCK. Therefore, CCK seems to be an important regulation factor in response to anticipatory stress.     

Biochemical changes in a 100 km run: proteins in serum and urine.

Eleven male subjects took part in a 100 km running competition. Alterations in the total plasma protein and in ten individual plasma protein concentrations in blood and urine were measured prior to the run, immediately after and after 1 day of recovery. Five individual proteins showed a 7-10%, and lysozyme a 40%, increase in the plasma after the run. On the contrary, the haptoglobin concentration fell to 40% of its pre-race level. None of these variations were correlated with the plasma volume change. The present data showed a moderate hemolysis, as evidenced by plasma lysozyme and hemoglobin-haptoglobin binding. The urinary excretion of plasma proteins was slightly increased, especially albumin and alpha1-acid-glycoprotein. The renal clearance of plasma proteins revealed that the 100 km run induced a moderate increase of glomerular permeability without any signficant change in the tubular reabsorption process.     

Tibiotalar cartilage stress corresponds to T2 mapping: application to barefoot running in novice and marathon-experienced runners

Abstract

A 3D anatomically-based finite-element foot model was adopted for predicting von Mises stresses within tibiotalar cartilage following 5?km barefoot running. To compare this predicted stress with T2 maps, magnetic resonance scans of the right ankle and plantar pressure were obtained from ten novices and ten marathon-experienced runners before and after running. Following running, tibiotalar cartilage stress was decreased in experienced runners. This corresponded with T2 values that did not change between pre- and post-running suggesting no increase in cartilage fluid levels. In contrast, novices maintained the same level of von Mises stress and this corresponded with a significant T2 increase in tibiotalar cartilage.     

The influence of weekly training distance on fractional utilization of maximum aerobic capacity in marathon and ultramarathon runners

This study was designed to examine the interrelationships between performance in endurance running events from 10 to 90 km, training volume 3-5 weeks prior to competition, and the fractional utilization of maximal aerobic capacity (%VO2max) during each of the events. Thirty male subjects underwent horizontal treadmill testing to determine their VO2max, and steady-state VO2 at specific speeds to allow for calculation of %VO2max sustained during competition. Runners were divided into groups of ten according to their weekly training distance (group A trained less than 60 km X week-1, group B 60 to 100 km X week-1, and group C more than 100 km X week-1). Runners training more than 100 km X week-1 had significantly faster running times (average 19.2%) in all events than did those training less than 100 km X week-1. VO2max or %VO2max sustained during competition was not different between groups. The faster running speed of the more trained runners, running at the same %VO2max during competition, was due to their superior running economy (19.9%). Thus all of the group differences in running performance could be explained on the basis of their differences in running economy. These findings suggest either that the main effect of training more than 100 km X week-1 may be to increase running economy, or that runners who train more than 100 km X week-1 may have inherited superior running economy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Probing softness of the parietal pleural surface at the micron scale

The pleural surfaces of the chest wall and lung slide against each other, lubricated by pleural fluid. During sliding motion of soft tissues, shear induced hydrodynamic pressure deforms the surfaces, promoting uniformity of the fluid layer thickness, thereby reducing friction. To assess pleural deformability at length scales comparable to pleural fluid thickness, we measured the modulus of the parietal pleura of rat chest wall using atomic force microscopy (AFM) to indent the pleural surface with spheres (radius 2.5 and 5 μm). The pleura exhibited two distinct indentation responses depending on location, reflecting either homogeneous or significantly heterogeneous tissue properties. We found an elastic modulus of 0.38-0.95 kPa, lower than the values measured using flat-ended cylinders >100 μm radii (Gouldstone et al., 2003, Journal of Applied Physiology 95, 2345-2349). Interestingly, the pleura exhibited a three-fold higher modulus when probed using 2.5 vs. 5 μm spherical tips at the same normalized depth, confirming depth dependent inhomogeneous elastic properties. The observed softness of the pleura supports the hypothesis that unevenness of the pleural surface on this scale is smoothed by local hydrodynamic pressure.     

Morphological and mechanical properties of muscle and tendon in highly trained sprinters

The purpose of this study was to investigate muscle and tendon properties in highly trained sprinters and their relations to running performance. Fifteen sprinters and 15 untrained subjects participated in this study. Muscle thickness and tendon stiffness of knee extensors and plantar flexors were measured. Sprinter muscle thickness was significantly greater than that of the untrained subjects for plantar flexors, but not for knee extensors (except for the medial side). Sprinter tendon stiffness was significantly lower than that of the untrained subjects for knee extensors, but not for plantar flexors. The best official record of a 100-m race was significantly correlated to the muscle thickness of the medial side for knee extensors. In conclusion, the tendon structures of highly trained sprinters are more compliant than those of untrained subjects for knee extensors, but not for plantar flexors. Furthermore, a thicker medial side of knee extensors was associated with greater sprinting performance.     

The energy cost of running increases with the distance covered

The net energy cost of running per unit of body mass and distance (Cr, ml O2.kg-1.km-1) was determined on ten amateur runners before and immediately after running 15, 32 or 42 km on an indoor track at a constant speed. The Cr was determined on a treadmill at the same speed and each run was performed twice. The average value of Cr, as determined before the runs, amounted to 174.9 ml O2.kg-1.km-1, SD 13.7. After 15 km, Cr was not significantly different, whereas it had increased significantly after 32 or 42 km, the increase ranging from 0.20 to 0.31 ml O2.kg-1.km-1 per km of distance (D). However, Cr before the runs decreased, albeit at a progressively smaller rate, with the number of trials (N), indicating an habituation effect (H) to treadmill running. The effects of D alone were determined assuming that Cr increased linearly with D, whereas H decreased exponentially with increasing N, i.e. Cr = Cr0 + a D + He-bN. The Cr0, the "true" energy cost of running in nonfatigued subjects accustomed to treadmill running, was assumed to be equal to the average value of Cr before the run for N equal to or greater than 7 (171.1 ml O2.kg-1.km-1, SD 12.7; n = 30).(ABSTRACT TRUNCATED AT 250 WORDS)     

Stress distribution in cylindrical and conical implants under rotational micromovement with different boundary conditions and bone properties: 3-D FEA

Factors related to micromovements at bone-implant interface have been studied because they are considered adverse to osseointegration. Simplifications are commonly observed in these FEA evaluations. The aim of this study was to clarify the influence of FEA parameters (boundary conditions and bone properties) on the stress distribution in peri-implant bone tissue when micromovements are simulated in implants with different geometries. Three-dimensional models of an anterior section of the jaw with cylindrical or conical titanium implants (4.1 mm in width and 11 mm in length) were created. Micromovement (50, 150, or 250 μm) was applied to the implant. The FEA parameters studied were linear vs. non-linear analyses, isotropic vs. orthogonal anisotropic bone, friction coefficient (0.3) vs. frictionless bone-implant contact. Data from von Mises, shear, maximum, and minimum principal stresses in the peri-implant bone tissue were compared. Linear analyses presented a relevant increase of the stress values, regardless of the bone properties. Frictionless contact reduced the stress values in non-linear analysis. Isotropic bone presented lower stress than orthogonal anisotropic. Conical implants behave better, in regard to compressive stresses (minimum principal), than cylindrical ones, except for nonlinear analyses when micromovement of 150 and 250 μm were simulated. The stress values raised as the micromovement amplitude increased. Non-linear analysis, presence of frictional contact and orthogonal anisotropic bone, evaluated through maximum and minimum principal stress should be used as FEA parameters for implant-micromovement studies.     

Healthy older adults have insufficient hip range of motion and plantar flexor strength to walk like healthy young adults

Limited plantar flexor strength and hip extension range of motion (ROM) in older adults are believed to underlie common age-related differences in gait. However, no studies of age-related differences in gait have quantified the percentage of strength and ROM used during gait. We examined peak hip angles, hip torques and plantar flexor torques, and corresponding estimates of functional capacity utilized (FCU), which we define as the percentage of available strength or joint ROM used, in 10 young and 10 older healthy adults walking under self-selected and controlled (slow and fast) conditions. Older adults walked with about 30% smaller hip extension angle, 28% larger hip flexion angle, 34% more hip extensor torque in the slow condition, and 12% less plantar flexor torque in the fast condition than young adults. Older adults had higher FCU than young adults for hip flexion angle (47% vs. 34%) and hip extensor torque (48% vs. 27%). FCUs for plantar flexor torque (both age groups) and hip extension angle (older adults in all conditions; young adults in self-selected gait) were not significantly <100%, and were higher than for other measures examined. Older adults lacked sufficient hip extension ROM to walk with a hip extension angle as large as that of young adults. Similarly, in the fast gait condition older adults lacked the strength to match the plantar flexor torque produced by young adults. This supports the hypothesis that hip extension ROM and plantar flexor strength are limiting factors in gait and contribute to age-related differences in gait.     

Influence of fluid intake on endurance running performance A comparison between water, glucose and fructose solutions

The aim of the present study was to compare the influence of drinking water, a carbohydrate-electrolyte solution, containing additional free glucose (Glucose) or the same carbohydrate-electrolyte solution containing additional fructose (Fructose), on running performance. Twelve endurance-trained recreational runners volunteered to take part in this study; 9 completed the three and all 12 completed two trials. The subjects were randomly assigned to one of the three trials: Water, Glucose or Fructose. In each trial the subjects were required to run 30 km as fast as possible on a motorized treadmill, instrumented so that they could control its speed. The carbohydrate-electrolyte solutions contained a total of 50 g carbohydrate, 20 g as a glucose polymer. The Glucose solution contained an additional 20 g free glucose and the Fructose solution contained an additional 20 g fructose rather than glucose. The osmolality of the Glucose and Fructose solutions was approximately 300-320 mosmol and the energy equivalent of both solutions was 794 kJ.l-1. The subjects ingested 1 l fluid throughout each run. The running times were not significantly different, being 129.3 (+/- 17.7) min, 124.8 (+/- 14.9) min and 125.9 (+/- 17.9) min for Water, Glucose and Fructose respectively. There was a decrease (P less than 0.05) in running speed over the last 10 km of the Water trial from 4.14 (+/- 0.55) to 3.75 (+/- 0.86) m.s-1, which did not occur in the carbohydrate trials. Blood glucose concentrations during the Water trial decreased from 15 km onwards and at the end of the run they were significantly (P less than 0.05) lower than the value recorded at 15 km.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of plantar flexor muscle fatigue on postural control

Objective

Previous studies have demonstrated that ankle muscle fatigue alters postural sway. Our aim was to better understand postural control mechanisms during upright stance following plantar flexor fatigue.

Method

Ten healthy young volunteers, 25.7 ± 2.2 years old, were recruited. Foot center-of-pressure (CoP) displacement data were collected during narrow base upright stance and eyes closed (i.e. blindfolded) conditions. Subjects were instructed to stand upright and as still as possible on a force platform under five test conditions: (1) non-fatigue standing on firm surface; (2) non-fatigue standing on foam; (3) ankle plantar flexor fatigue, standing on firm surface; (4) ankle plantar flexor fatigue, standing on foam; and (5) upper limb fatigue, standing on firm surface. An average of the ten 30-s trials in each of five test conditions was calculated to assess the mean differences between the trials. Traditional measures of postural stability and stabilogram-diffusion analysis (SDA) parameters were analyzed.

Results

Traditional center of pressure parameters were affected by plantar flexor fatigue, especially in the AP direction. For the SDA parameters, plantar flexor fatigue caused significantly higher short-term diffusion coefficients, and critical displacement in both mediolateral (ML) and anteroposterior (AP) directions. Long-term postural sway was different only in the AP direction.

Conclusions

Localized plantar flexor fatigue caused impairment to postural control mainly in the Sagittal plane. The findings indicate that postural corrections, on average, occurred at a higher threshold of sway during plantar flexor fatigue compared to non-fatigue conditions.