Propulsive Phase Research Articles

Performance Level Affects Full Body Kinematics and Spatiotemporal Parameters in Trail Running-A Field Study.

Trail running is an emerging discipline with few studies performed in ecological conditions. The aim of this work was to investigate if and how biomechanics differ between more proficient (MP) and less proficient (LP) trail runners. Twenty participants (10 F) were recruited for a 9.1 km trail running time trial wearing inertial sensors. The MP athletes group was composed of the fastest five men and the fastest five women. Group differences in spatiotemporal parameters and leg stiffness were tested with the Mann-Whitney U-test. Group differences in joint angles were tested with statistic parametric mapping. The finish time was 51.1 ± 6.3 min for the MP athletes and 60.0 ± 5.5 min for the LP athletes (p < 0.05). Uphill sections: The MP athletes expressed a tendency to higher speed that was not significant (p > 0.05), achieved by combining higher step frequency and higher step length. They showed a tendency to shorter contact time, lower duty factor and longer flight time that was not significant (p > 0.05) as well as significantly lower knee flexion during the stance phase (p < 0.05). Downhill sections: The MP athletes achieved significantly higher speed (p < 0.05) through higher step length only. They showed significantly higher knee and hip flexion during the swing phase as well as higher trunk rotation and shoulder flexion during the stance phase (p < 0.05). No differences were found with respect to leg stiffness in the uphill or downhill sections (p > 0.05). In the uphill sections, the results suggest lower energy absorption and more favorable net mechanical work at the knee joint for the MP athletes. In the downhill sections, the results suggest that the more efficient motion of the swing leg in the MP athletes could increase momentum in the forward direction and full body center of mass' velocity at toe off, thus optimizing the propulsion phase.

Effect of Repeated, On-Field Sprints on Kinematic Variables in Wheelchair Rugby Players.

The aim of the study was to evaluate the influence of repeated sprints on kinematic performance and propulsion variables during the acceleration and constant peak velocity phases in wheelchair rugby players classified as defensive (low point in defensive [LP-D]) or offensive players (high point in offensive [HP-O]). Twenty-two players (13 LP-D and 9 HP-O) performed 6 × 20-m repeated sprint field tests. We calculated peak wheelchair velocities, propulsion phase times, deceleration phase times, cycle times, and left-right velocity asymmetry of the best and last sprints during the acceleration and constant peak velocity phases, the rate of decline in performance variables between the best and the last sprint and a fatigue index. Peak velocities during the acceleration and constant peak velocity phases and mean velocity over the whole sprint were significantly higher during the best than last sprint. Peak velocities were higher during the acceleration and constant peak velocity phases for the best and last sprint for HP-O. The rate of decline in peak velocity during the constant peak velocity phase was higher for LP-D. Fatigue index and rate of decline in velocities and sprint time were higher for LP-D. Performance variables and the rate of decline in performance variables depended on functional capacity and wheelchair type.

The Effects of Accentuated Eccentric Loading on Barbell and Trap Bar Countermovement Jumps

This study examined effects of accentuated eccentric loading (AEL) on barbell and trap bar loaded countermovement jumps (LCMJ). Twenty-one subjects (16 male, 5 female; Age: 23.5 ± 1.8 years; Body mass: 81.4 ± 10.6 kg; Height: 176.9 ± 7.2 cm; Training age: 7.1 ± 2.6 years) participated in this study. Upon establishing one repetition maximum and baseline jumping conditions, three experimental loading sessions were completed in random order. Barbell and trap bar LCMJ were performed with a spectrum of fixed loads from 20-50 kg during control conditions and with additional AEL loads of 10, 20, or 30 kg for experimental conditions. According to coefficients of variation (&lt;10%), jump height, modified reactive strength index (mRSI), force, impulse, and duration measures were considered reliable across conditions. Mixed effect models analyzed effects of AEL against fixed loading in trap bar and barbell LCMJ (p &lt; 0.05). Compared to the control condition, AEL produced negligible reductions in jump height during barbell LCMJ and small reductions during trap bar LCMJ. Modified reactive strength indexes were reduced by AEL during barbell LCMJ but not trap bar LCMJ. Average braking forces were greater in AEL conditions, while propulsive impulse was lower in the AEL conditions. The barbell LCMJ with AEL resulted in longer propulsive durations and unchanged braking durations, while propulsive and braking durations were lower during trap bar LCMJ with AEL compared to control conditions. This investigation revealed that use of AEL increases eccentric braking forces but decreases propulsive phase outputs, which subsequently may result in negligible to small acute decreases in LCMJ height. Implementing AEL during LCMJ may be an effective strategy to improve deceleration / eccentric abilities. Future research should explore longitudinal power and deceleration adaptations, while concomitantly improving acutely altered movement mechanics from AEL.

Increasing load carriage and running speed differentially affect the magnitude, variability and coordination patterns of muscle forces

The study aims to investigate the effects of different loads and speed during running on inter- and intra-individual muscle force amplitudes, variabilities and coordination patterns. Nine healthy participants ran on an instrumentalized treadmill with an empty weight vest at two velocities (2.6 m/s and 3.3 m/s) or while carrying three different loads (4.5, 9.1, 13.6 kg) at 2.6 m/s while kinematics and kinetics were synchronously recorded. The major lower limb muscle forces were estimated using a musculoskeletal model. Muscle force amplitudes and variability, as well as coordination patterns were compared at the group and at the individual level using respectively statistical parametric mapping and covariance matrices combined with multidimensional scaling. Increasing the speed or the load during running increased most of the muscle force amplitudes (p < 0.01). During the propulsion phase, increasing the load increased muscle force variabilities around the ankle joint (modification of standard deviation up to 5% of body weight (BW), p < 0.05) while increasing the speed decreased variability for almost all the muscle forces (up to 10% of BW, p < 0.05). Each runner has a specific muscle force coordination pattern signature regardless of the different experimental conditions (p < 0.05). Yet, this individual pattern was slightly adapted in response to a change of speed or load (p < 0.05). Our results suggest that adding load increases the amplitude and variability of muscle force, but an increase in running speed decreases the variability. These findings may help improve the design of military or trail running training programs and injury rehabilitation by progressively increasing the mechanical load on anatomical structures.

The clinical and biomechanical effects of customized foot orthoses in individuals with plantar heel pain: A pre-post intervention study

BackgroundCustomized foot orthoses (CFOs) are often recommended for the management of plantar heel pain. However, there is a lack of information regarding lower limb and multi-segment foot motion during gait. Research questionThis study aimed to determine the effects of heat moulded CFOs on foot and lower limb kinematics when compared with prefabricated foot orthoses (PFOs) and wearing no orthoses (shod condition), and to determine the short-term effects of CFOs on pain intensity and foot function. MethodsThe immediate effects of CFOs on the lower limb and multi-segment foot motion were assessed. Participants were then asked to use the CFOs for one month and foot pain, function, and temporal-spatial parameters were assessed at baseline and at one month follow up. ResultsThirty-five participants (22 females), aged 40.1 (10.5) years, with a mean duration of symptoms of 12.59 months were recruited. The symptomatic limbs showed a higher forefoot varus angle and greater rearfoot and forefoot corrections were required compared to the non-symptomatic limbs. When compared with PFOs and shod conditions, CFOs provided the least forefoot and knee motion in the transverse plane during contact phase (P < 0.05, d=0.844–1.720), least rearfoot motion in the coronal plane during midstance (P < 0.05, d=0.652), and least forefoot motion in the frontal plane, knee motion in the transverse plane, and hallux motion during the propulsive phase (P < 0.05, d=0.921–1.513). Significant improvements were seen for foot pain and function (P < 0.05, d=1.390–2.231) with significant increases in cadence and walking velocity after one month of CFO use (P < 0.05, d=0.315–0.353), and those most likely to respond had greater pain and less ankle eversion (P < 0.05, d=0.855–1.115). SignificanceCFOs appear to improve pathological biomechanics associated with plantar heel pain. After one month follow up, the CFOs decreased pain intensity and increased foot function, and showed significant improvements in temporal and spatial parameters of gait.

Comparison of swimming velocity between age-group swimmers through discrete variables and continuous variables by Statistical Parametric Mapping

ABSTRACT The aim of this study was to compare the swimming velocity in front-crawl between age-group swimmers using discrete variables against Statistical Parametric Mapping (SPM). The sample consisted of 30 young male swimmers divided into three groups (each with 10 swimmers) based on their age (group #1: 13.60 ± 0.84 years; group #2: 15.40 ± 0.32 years; group 3: 16.39 ± 0.69 years). Swimmers performed three maximal trials in front-crawl. The best performance was used for analysis. Comparison of swimming velocity between groups was analysed using discrete variables and as a continuous variable (SPM). As a discrete variable, the mean swimming velocity showed a significant difference between groups (p < 0.05). Moreover, when analysed by SPM, swimming velocity showed a significant difference (p = 0.021) between the ~ 44% and ~ 51% of the stroke cycle (transition of the propulsion phases between sides). Post-hoc comparison revealed a significant difference between group #1 and group #3 only in SPM analysis. Researchers, coaches, and practitioners should know that both measurement approaches can be used simultaneously. However, SPM offers more sensitive and accurate results about the swimmers’ stroke cycle.

Role of kinesiophobia in the selective motor control during gait in patients with low back-related leg pain.

Fear of movement has been related to changes in motor function in patients with low back pain, but little is known about how kinesiophobia affects selective motor control during gait (ability of muscles performing distinct mechanical functions) in patients with low back-related leg pain (LBLP). The aim of the study was to determine the association between kinesiophobia and selective motor control in patients with LBLP. An observational cross-sectional study was performed on 18 patients. Outcome included: kinesiophobia using the Tampa Scale of Kinesiophobia; pain mechanism using Leeds Assessment of Neuropathic Signs and Symptoms; disability using Roland-Morris Disability Questionnaire; mechanosensitivity using Straight Leg Raise. Surface electromyography was used to assess selective motor control during gait by examining the correlation and coactivation in muscle pairs involved in the stance phase. Pairs included vastus medialis (VM) and medial gastrocnemius (MG), causing opposite moments around the knee joint, and gluteus medius (GM) and MG, as muscles with distinct mechanical functions (weight acceptance vs. propulsion). A strong association was observed between kinesiophobia and correlation (r=0.63; p=0.005) and coactivation (r=0.69; p=0.001) between VM versus MG. A moderate association was observed between kinesiophobia and correlation (r=0.58; p=0.011) and coactivation (r=0.55; p=0.019) between GM versus MG. No significant associations were obtained for other outcomes. A high kinesiophobia is associated with low selective motor control of the muscles involved in the weight acceptance and propulsion phases during gait in patients with LBLP. Fear of movement was better associated with decreased neuromuscular control than other clinical variables such as pain mechanism, disability, and mechanosensitivity.

Functional relationship between the foot intrinsic and extrinsic muscles in walking.

The intrinsic and extrinsic muscles are considered to stabilize the foot and contribute to propulsion during walking. This study aimed to clarify the functional relationship between intrinsic and extrinsic muscles during walking. Thirteen healthy men participated in this study. The muscle activities of the intrinsic muscles (quadratus plantae and abductor hallucis), and the extrinsic muscles (flexor hallucis longus, flexor digitorum longus, and tibialis posterior) were measured using fine-wire and surface electromyography during walking. The muscle onset timing after foot contact was calculated and compared among muscles using the one-way ANOVA. The stance phase was divided into early and late braking, and early and late propulsion phases. Muscle activity among phases was compared using repeated-measures ANOVA. The onset time of the abductor hallucis was significantly earlier than those of the flexor digitorum longus and tibialis posterior. The quadratus plantae demonstrated significantly earlier onset than that of the tibialis posterior. In the late propulsion phase, the activity of extrinsic muscles decreased, whereas intrinsic muscles were continuously active. Early activation of the intrinsic muscles may stabilize the foot for efficient torque production by the extrinsic muscles. Furthermore, the intrinsic muscles may contribute to the final push-off after the deactivation of extrinsic muscles.

Ankle-Specific Training Does Not Alter Drop Jumping Biomechanics Despite Increased Plantar Flexor Strength and Jumping Performance.

Power plays a crucial role in determining an athlete's final performance, as it signifies the ability to rapidly generate force. The plantar flexor muscles have a crucial role in producing the necessary power. The plantar flexor muscles are important in explosive sports movements due to their ability to generate substantial force quickly during the propulsion phase and facilitate efficient energy transfer through the joints. This study aimed to investigate the effects of specific plantar flexor training on drop jumping (DJ) biomechanics, muscle activation, and muscle strength. A total of 30 male participants were divided into three groups: the incline hopping(IH) group, which performed continuous jumps on a 15° inclined surface; the plane hopping (PH) group, which performed jumps on a plane surface; and the electrostimulation(EMS) group (n = 10 for each group). All groups trained four times weekly, performing 10 sets of 10 jumps per session. The intervention period lasted four weeks. Participants' drop jumping ability was assessed before and immediately after the training period using hip, knee, and ankle kinematics and electromyographic (EMG) activity of the medial gastrocnemius (MGas), tibialis anterior (TA), rectus femoris (RF), and semitendinosus (ST) muscles. In addition, maximal isokinetic plantar flexor force measurements were evaluated in eccentric and concentric conditions. Analysis of variance (ANOVA) revealed that only the inclined hopping showed significant improvements in the take-off velocity (Vto) of the fast drop jump (bounce drop jump (BDJ)) (p < 0.05). These improvements were accompanied by significantly higher MGas activity during the propulsion phase of the jump (p < 0.05). In addition, all groups demonstrated greater eccentric torque (p < 0.05), while IH also improved concentric torque (p < 0.05). The results support the efficacy of inclined hopping in improving the Vto of BDJs. The increased MGas activity and stable co-activation index (CI) during the propulsion phase are likely to contribute to these improvements. Coaches should consider incorporating incline hopping into the periodization of athletes, while level hopping and electrostimulation could be used to increase overall strength.

Crural and Plantar Fasciae Changes in Chronic Charcot Diabetic Foot: A Cross-Sectional Ultrasound Imaging Study-An Evidence of Fascial Continuity.

Crural fascia (CF) and plantar fascia (PF) are biomechanically crucial in the gait and in the proprioception, particularly in the propulsion phase of the foot during the gait cycle and in the dissipation of forces during weight-bearing activities. Recent studies have revealed an association between increases in PF thickness and diabetes. The purpose of this study was to measure and compare by ultrasound (US) imaging the thickness of the CF and PF at different regions/levels in chronic Charcot diabetic foot patients (group 1) and in healthy volunteers (group 2). A cross-sectional study was performed using US imaging to measure the CF with Pirri et al.'s protocol and PF with a new protocol in a sample of 31 subjects (15 patients and 16 healthy participants). The findings for CF and PF revealed statistically significant differences in the poster region of CF (Post 1: group 1 vs. group 2: p = 0.03; Post 2: group 1 vs. group 2: p = 0.03) and in PF at two different levels (PF level 1: group 1 vs. group 2: p < 0.0001; PF level 2: group 1 vs. group 2: p < 0.0001). These findings suggest that chronic Charcot diabetic foot patients have CF and PF thicker compared to healthy volunteers. The US examination suggests that fascial thicknesses behavior in these patients points out altered fascial remodeling due to diabetes pathology and biomechanical changes.

Effect of Footwear Type on Biomechanical Risk Factors for Knee Osteoarthritis.

Regular walking in different types of footwear may increase the mediolateral shear force, knee adduction moment, or vertical ground-reaction forces that could increase the risk of early development of knee osteoarthritis (OA). To compare kinematic and kinetic parameters that could affect the development of knee OA in 3 footwear conditions. Controlled laboratory study. A total of 40 asymptomatic participants performed walking trials in the laboratory at self-selected walking speeds under barefoot (BF), minimalistic (MF), and neutral (NF) footwear conditions. Knee joint parameters were described using discrete point values, and continuous curves were evaluated using statistical parametric mapping. A 3 × 1 repeated-measures analysis of variance was used to determine the main effect of footwear for both discrete and continuous data. To compare differences between footwear conditions, a post hoc paired t test was used. Discrete point analyses showed a significantly greater knee power in NF compared with MF and BF in the weight absorption phase (P < .001 for both). Statistical parametric mapping analysis indicated a significantly greater knee angle in the sagittal plane at the end of the propulsive phase in BF compared with NF and MF (P = .043). Knee joint moment was significantly greater in the propulsive phase for the sagittal (P = .038) and frontal planes (P = .035) in BF compared with NF and MF and in the absorption phase in the sagittal plane (P = .034) in BF compared with MF and NF. A significant main effect of footwear was found for anteroposterior (propulsion, ↑MF, NF, ↓BF [P = .008]; absorption, ↑BF, MF, ↓NF [P = .001]), mediolateral (propulsion, ↑MF, NF, ↓BF [P = .005]; absorption, ↑NF, MF, ↓BF [P = .044]), and vertical (propulsion, ↑NF, BF, ↓MF [P = .001]; absorption, ↑MF, BF, ↓NF [P < .001]) ground-reaction forces. Knee power showed a significant main effect of footwear (absorption, ↑NF, MF, ↓BF [P = .015]; propulsion, ↑MF, NF, ↓BF [P = .039]). Walking in MF without sufficient accommodation affected kinetic and kinematic parameters and could increase the risk of early development of knee OA.

The influence of first ray instability and hindfoot valgus in the development of hallux rigidus: state of art.

Hallux rigidus (HR) is a painful condition associated with degenerative arthritis of the first metatarsophalangeal (MTP1) joint, leading to a progressive loss of dorsiflexion. The etiological factors leading to the development of the condition are not yet fully understood in the literature. When the hindfoot is aligned in excessive valgus, the medial border of the foot tends to roll over, which brings to increased stress on the medial side of the MTP1 joint, and consequently on the first ray (FR), thus potentially influencing the development of HR deformity. This state of art aims to analyze the influence of FR instability and hindfoot valgus in HR development. From the results of the analyzed studies, it appears that a FR instability may predispose the big toe to increased stress and to narrow the proximal phalanx motion on the first metatarsal, which brings to compression and ultimately degeneration of the MTP1 joint, mostly in advanced stages of disease, less in mild or moderate HR patients. A strong correlation between a pronated foot and MTP1 joint pain was found; forefoot hypermobility during the propulsion phase may promote MTP1 joint instability and increase pain. Thus, the increased moment of pronation of the foot with the overload of the medial column, when present, should be corrected conservatively or surgically; this, most likely, would be useful not only to eliminate or at least limit the painful symptoms but above all to prevent the worsening of the condition, also after the surgical treatment of HR.

Muscle function during cross-country skiing at different speed and incline conditions.

The human musculoskeletal system is well adapted to use energy-efficient muscle-tendon mechanics during walking and running, but muscle behaviour during on-snow locomotion is unknown. Here, we examined muscle and muscle-tendon unit behaviour during diagonal-style cross-country roller skiing at three speed and incline conditions to examine whether skiers can exploit energy-saving mechanisms of the muscle-tendon unit. We assessed lower leg muscle and muscle-tendon unit mechanics and muscle activity in 13 high-level skiers during treadmill roller skiing using synchronised ultrasound, motion capture, electromyography and ski-binding force measurements. Participants skied using diagonal style at 2.5 and 3.5 m s-1 up 5deg, and at 2.5 m s-1 up 10deg. We found an uncoupling of muscle and joint behaviour during most parts of the propulsive kick phase in all conditions (P<0.01). Gastrocnemius muscle fascicles actively shortened ∼0.9 cm during the kick phase, while the muscle-tendon unit went through a stretch-shortening cycle. Peak muscle-tendon unit shortening velocity was 5 times faster than fascicle velocity (37.5 versus 7.4 cm s-1, P<0.01). Steeper incline skiing was achieved by greater muscle activity (24%, P=0.04) and slower fascicle shortening velocity (3.4 versus 4.5 cm s-1, P<0.01). Faster speed was achieved by greater peak muscle activity (23%, P<0.01) and no change in fascicle shortening velocity. Our data show that, during diagonal-style cross-county skiing, muscle behaviour is uncoupled from the joint movement, which enables beneficial contractile conditions and energy utilisation with different slopes and speeds. Active preloading at the end of the glide phase may facilitate these mechanisms.

Concomitant Triceps Surae Lengthening in Total Ankle Arthroplasty Affects the Mechanical Work at the Ankle Joint.

Previous studies have examined the effect of concomitant triceps surae lengthening on ankle dorsiflexion motion at the time of total ankle arthroplasty (TAA). As plantarflexor muscle-tendon structures are important for producing positive ankle work during the propulsive phase of gait, caution should be exercised when lengthening triceps surae, as it may decrease plantarflexion strength. In order to develop an understanding of the work of the anatomical structures crossing the ankle during propulsion, joint work must be measured. The aim of this explorative study was to assess the effect of concomitant triceps surae lengthening with TAA on the resultant ankle joint work. Thirty-three patients were recruited to the study and divided into 3 groups of 11. The first group underwent both triceps surae lengthening (Strayer and TendoAchilles) and TAA (Achilles group), the second group underwent only TAA (Non-Achilles group), and the third group underwent only TAA, but had a greater radiographic prosthesis range of motion (Control group) compared to the first 2 groups. The 3 groups were matched in terms of demographic variables and walking speed. All patients underwent a 3D gait analysis 1 year after surgery to measure intersegmental joint work using a 4-segmented kinetic foot model. An analysis of variance (ANOVA) or Kruskal-Wallis test was used to compare the 3 groups. The ANOVA showed significant differences between the 3 groups. Post hoc analyses suggested that (1) the Achilles group had less positive work at the ankle joint than the Non-Achilles and Control groups; (2) the Achilles group produced less positive work performed by all foot and ankle joints than the Control group; and (3) the Achilles and Non-Achilles groups absorbed less energy across all foot and ankle joints during the stance phase than the Control group. Concomitant triceps surae lengthening in TAA may reduce the positive work at the ankle joint. Level III, retrospective comparative study.

Einfluss einer 3D-gedruckten bionischen Fußorthese auf die Rückfußbelastung und Laufökonomie

BackgroundDuring the propulsion phase (PP) of running, the greatest internal loads occur at the feet. An intact windlass mechanism (WM) is essential for physiological loading at the feet during PP and energy-efficient locomotion. In functional flat foot deformity, WM is insufficient. Overstressing can be the result. In addition, energy efficiency during running is reduced. Foot orthoses (FO) are used, among other things, to optimize positioning and loading of the lower extremities. Optimization of loading during PP and optimization of running economy have not been the focus of FO treatments. A 3D-printed bionic (BFO) is developed to improve loading in PP and to improve energy efficiency during running. The aim of the present study was to determine the influences of BFO on loading in the subtalar region and on running economy. Material and MethodsThirteen subjects with functional pes valgus (39 ± 7 J, 8 m) participated in the study. The subjects ran in randomized order under 4 conditions: without FO (oFO), supportive FO (CFO), sensorimotor FO (SMFO), and BFO on a treadmill. The vebitoScience measurement system (120 Hz) was used to detect torsional moments, respectively pronation/supination load in the subtalar region and time-related parameters. The influences of FO on running economy were determined by stance phase duration, PP, and AP. Statistical analysis was performed using one-way ANOVA with repeated measures and Pearson correlation. ResultsDuring AP, pronation loading occurs in oFO, CFO, and BFO conditions, and supination loading occurs in SMFO condition. All conditions differ significantly from each other. Pronation loading occurs under conditions oFO and SMFO, and supination loading occurs under conditions CFO and BFO during PP. BFO is significantly different from all other conditions. The duration of AP during running with BFO is significantly shorter and the duration of PP is significantly longer than in the other conditions. The duration of PP and supination load while PP correlate significantly strongly for both, FO and BFO. ConclusionsAll FO tested have significant influences on subtalar loading during AP. In subjects with pes valgus, lower supination loading during PP is significantly related to lower running economy. BFO significantly increases supination loading in the subtalar region during PP. The duration of the PP is significantly prolonged by BFO. This represents an optimization of running economy. The other FO tested do not provide these influences. In addition, there is a significant relationship between the greater supination load and better running economy with BFO. In conclusion, BFO have positive influences on loading and running economy in runners with pes valgus.

Effects of customized insoles with medial wedges on lower extremity kinematics and ultrasonographic findings in plantar fasciitis persons

The customized insole is widely recommended as an effective intervention for pain reduction and foot function improvement in plantar fasciitis persons. However, it is unclear whether the additional correction of medial wedges could change the kinematics from the only insole. The objectives of this study were thus to compare customized insoles with and without medial wedges on lower extremity kinematics during gait and to determine the short-term effects of the customized insole with medial wedges on pain intensity, foot function, and ultrasonographic findings in plantar fasciitis persons. A within-subject, randomized, crossover design within motion analysis research laboratory was conducted among 35 persons with plantar fasciitis. Main outcome measures included joint motions of the lower extremity and multi-segment foot, pain intensity, foot function, and ultrasonographic findings. The customized insole with medial wedges produced less knee motion in the transverse plane and hallux motion in all planes during the propulsive phase than that without medial wedges (all p < 0.05). After the 3-month follow-up, the insoles with medial wedges decreased pain intensity and increased foot function. Abnormal ultrasonographic findings also decreased significantly after the 3-month treatment of insoles with medial wedges. Customized insoles with medial wedges seem superior to those without medial wedges on both multi-segment foot motion and knee motion during propulsion. Positive outcomes from this study supported the use of customized insoles with medial wedges as an effective conservative treatment in patients with plantar fasciitis.Trial registration: TCTR20210928006 (28/09/2021).

Foot kinematics in runners with plantar heel pain during running gait

BackgroundPlantar heel pain associated with plantar fascia pathology (PHP) is one of the most common running overuse injuries. Degeneration and changes in the mechanical properties of the plantar fascia associated with PHP can result in changes in foot kinematics during gait. Research questionHow do running gait foot kinematics differ between female and male runners with and without PHP? MethodsRetrospective study of 13 runners with PHP (7 female, 6 male) and a matched group of 13 uninjured runners (6 female, 7 male). A seven-segment foot model was used to quantify six functional articulations (rearfoot complex, lateral and medial midfoot, lateral and medial forefoot, and first metatarsophalangeal). Functional articulation ROM during early, mid, and propulsion running stance subphases was assessed. Two-way ANOVAs and Friedman’s two-way ANOVA for ranks tests were conducted for normally distributed variables and non-normally distributed variables, respectively. ResultsDuring early stance, PHP runners demonstrated significantly increased lateral midfoot eversion ROM compared to uninjured runners. During the propulsion phase, male runners with PHP demonstrated increased medial midfoot eversion and dorsiflexion ROM and increased medial forefoot plantar flexion compared to uninjured male runners. Also during propulsion, females with PHP went through significantly less medial forefoot plantar flexion ROM compared to uninjured female runners. SignificanceGiven the function of the plantar fascia to assist foot supination, the differences in runners with PHP, which were consistent with increased pronation or inadequate supination, may be the result of insufficient tension during the stance phase of running gait caused by degeneration of the plantar fascia. Further, the significant medial midfoot and medial forefoot group by sex interactions during propulsion suggest that PHP may affect male and female runners differently. Understanding the effect of PHP on foot function during running may aid in the development of future rehabilitation programs and/or treatment outcome assessments.

Effects of athletic socks with high frictional properties on in-shoe foot sliding and performance in football-specific movements

The purpose of this study was to examine the efficacy of high friction socks on in-shoe foot sliding and running performance of male footballers during change of direction movements. Twelve recreational football players (mean age 20.3 ± 1.1 years) completed a 26 m dynamic agility course at their maximum running speed. 3D kinematic and kinetic data were collected for three maximum speed 45° side-cuts, and 180° turns in two different sock conditions. Comparisons were made between a sock with a high static coefficient of friction (GripSock) and a regular sock (CompressionS). The Gripsock condition significantly increased utilized traction (COFu) and a reduction of GRF angle (GRFα) was identified during the braking phase of the side cut (COFu: + 9.3 ± 10%; GRFα: −3.1 ± 2.9%) but not in the side-cut propulsion, turn braking and turn propulsion phases. Speed perception was raised in the GripSock condition (+18 ± 30%). However, wearing a sock with high frictional properties did not significantly reduce in-shoe foot sliding in any examined direction nor did it significantly reduce running times over a functional traction course. The relationship between in-shoe traction and running performance is complex and likely dependent on the overall interaction of shoe properties and the type of athletic sock.

Biomechanical adaptations during exhaustive runs at 90 to 120% of peak aerobic speed

The aim of this study was to examine how running biomechanics (spatiotemporal and kinetic variables) adapt with exhaustion during treadmill runs at 90, 100, 110, and 120% of the peak aerobic speed (PS) of a maximal incremental aerobic test. Thirteen male runners performed a maximal incremental aerobic test on an instrumented treadmill to determine their PS. Biomechanical variables were evaluated at the start, mid, and end of each run until volitional exhaustion. The change of running biomechanics with fatigue was similar among the four tested speeds. Duty factor and contact and propulsion times increased with exhaustion (P ≤ 0.004; F ≥ 10.32) while flight time decreased (P = 0.02; F = 6.67) and stride frequency stayed unchanged (P = 0.97; F = 0.00). A decrease in vertical and propulsive peak forces were obtained with exhaustion (P ≤ 0.002; F ≥ 11.52). There was no change in the impact peak with exhaustion (P = 0.41; F = 1.05). For runners showing impact peaks, the number of impact peaks increased (P ≤ 0.04; {upchi }^{2} ≥ 6.40) together with the vertical loading rate (P = 0.005; F = 9.61). No changes in total, external, and internal positive mechanical work was reported with exhaustion (P ≥ 0.12; F ≤ 2.32). Results suggest a tendency towards a “smoother” vertical and horizontal running pattern with exhaustion. A smoother running pattern refers to the development of protective adjustments, leading to a reduction of the load applied to the musculoskeletal system at each running step. This transition seemed continuous between the start and end of the running trials and could be adopted by the runners to decrease the muscle force level during the propulsion phase. Despite these changes with exhaustion, there were no changes in either gesture speed (no alteration of stride frequency) or positive mechanical work, advocating that runners unconsciously organize themselves to maintain a constant whole-body mechanical work output.

Effects of foot-ankle exercises on foot-ankle kinematics, plantar pressure, and gait kinetics in people with diabetic neuropathy: Secondary outcomes from a randomized controlled trial

BackgroundFollow-up report of secondary outcomes of a randomized, single-blinded, parallel controlled trial that investigated the benefits of a foot-ankle therapeutic exercise program on foot-ankle kinematics, plantar pressure, and lower limb kinetics during gait in individuals with diabetic neuropathy (DPN). MethodsSixty-six participants with DPN were randomly allocated into a control group (CG; n = 31), which received usual care, and an intervention group (IG; n = 35), which received usual care plus a 12-week group-based foot-ankle exercise program. Outcomes were assessed at baseline and 12 weeks by an assessor blinded to group allocation. ResultsThe generalized linear mixed model and intention-to-treat analysis revealed a greater hip extensor moment at push-off and greater hallux contact area in the IG than CG after 12 weeks. A within-group analysis revealed a larger arch height during stance and higher peak pressure and pressure-time integral at the central forefoot region in the IG after 12 weeks compared to baseline. There were no other significant group difference or changes over time in foot-ankle kinematics or in any other joint moment related to overall lower limb biomechanics. ConclusionThe increases in hip moment at push-off and hallux surface contact area suggest an improvement in the propulsion phase with greater participation of the toes in foot rollover after 12 weeks of a group-based foot-ankle exercises program for people with DPN. Individual face-to-face, longer-term, and more intensive interventions may be needed to positively influence foot-ankle biomechanics and pressure parameters in other plantar areas.