Heel Drop Research Articles

Bowling alleys in residential buildings—Noise control and measurements

In the competitive world of residential development, developers are striving to construct residential buildings that will be more desirable to occupants by providing a diverse range of amenity spaces, such as a bowling alley. Understandably, noise concerns from the addition of bowling alleys in residential buildings were raised during the design stage of various projects. To address the issues, a jack-up floating floor system was proposed for the bowling alley to mitigate the noise impact from the pin setting machine, initial ball impact on the bowling alley lanes, rolling on the lanes, and ball impact with the pins. Apparent Impact insulation class (AIIC) and heel drop testing were completed at various stages during the floating floor construction to confirm the impact sound isolation performance of the floating floor system. Testing results concluded that the implemented floating floor system reduced impact noise significantly and satisfactory sound levels resulted in the closest occupied spaces.

DIAGNOSTIC MARKERS IN ACUTE APPENDICITIS: A SYSTEMATIC REVIEW

Introduction: Appendicitis is the most common emergency case of abdominal surgery and requires immediate surgical intervention to avoid serious complications. If appendicitis is treated late, it will increase patient morbidity and mortality. Despite the relatively high incidence of needless appendectomies, ranging from 20% to 30%, such occurrences are deemed tolerable given the substantial reliability of beneficial outcomes.
 
 The aim: This article showed diagnostic markers in acute appendicitis.
 
 Methods: This study demonstrated compliance with all requirements by comparing itself to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 standards. Therefore, the experts were able to ensure that the study was as current as feasible. For this search strategy, publications published between 2013 and 2023 were considered. Several online reference sources, including Pubmed and SagePub, were utilized for this purpose. It was determined not to consider review pieces, previously published works, or works that were only partially completed.
 
 Result: The PubMed database yielded a total of 87 articles in response to our search query, while the search conducted on SagePub resulted in 69 articles. The search conducted for the last year of 2013 resulted in a total of 29 articles found in PubMed and 31 papers found in SagePub. Ultimately, a comprehensive compilation of 22 papers was achieved, with 15 sourced from PubMed and an additional seven obtained via SagePub. We incorporated seven studies that satisfied the established criteria.
 
 Conclusion: Study shows that a shift in pain from the epigastrium to the Mc Barney point and heel drop test is a sign of appendicitis based on physical examination. Examination of white blood cells and CRP can be other reliable markers to confirm acute appendicitis.

Intratendinous pressure of the Achilles tendon during exercise is related to the degree of tendon torsion.

Torsion of the Achilles tendon (AT) enhances tensile strength, but a high degree of torsion might also be a risk factor for Achilles tendinopathy, due to greater internal compression exerted during tensile loading. However, evidence supporting the grounds for this assumption is lacking. Hence, we aimed to investigate the impact of AT torsion type on intratendinous pressure. Eighteen human fresh frozen cadaveric legs were mounted in a testing rig and a miniature pressure catheter was placed through ultrasound-guided insertion in the midportion region of the AT. Intratendinous pressure was measured during a simulated straight-knee calf stretch and eccentric heel drop. The AT was then carefully dissected and classified into Type I (least), Type II (moderate), and Type III (extreme) torsion. Of the ATs examined, nine were found to have Type I torsion (50%), nine Type II (50%), and none Type III. It was found that the intratendinous pressure of the AT increased exponentially with ankle dorsiflexion during both exercises (p < 0.001) and that this increase was greater in ATs with Type II torsion than Type I torsion (p < 0.05). This study provides the first biomechanical data to support the hypothesis that in athletes with a high degree of torsion in the AT, the midportion area will experience more internal compression during exercise, for example, calf stretching and eccentric heel drops. Whether this phenomenon is also associated with an elevated risk for Achilles tendinopathy needs further prospective investigation.

Triceps surae muscle forces during dynamic exercises in patients with Achilles tendinopathy: A cross-sectional study.

The aim of this study was to investigate the individual triceps surae muscle forces during the execution of six different functional movements and rehabilitation exercises in patients with Achilles tendinopathy compared to a control group. Triceps surae muscle forces of 15 participants with Achilles tendinopathy (AT) and 15 healthy controls were estimated through a combination of experimental data and musculo-skeletal modeling. Three-dimensional motion capture and force plates were used to collect the ankle and knee joint angles and moments during three functional movements (walking, heel walking, and toe walking) and three rehabilitation exercises (bilateral heel drop, unilateral heel drop with extended knee and with flexed knee). A dynamic optimization method was used to obtain the modeled triceps surae muscle forces. Force-sharing strategies were calculated at the peak triceps surae muscle force and compared between groups. Lower peak triceps surae forces were obtained for the AT group during dynamic exercises. Across all exercises, the average contribution of the soleus (SOL) to the total triceps surae muscle force was the largest (60.83 ± 13.89% [AT] > 56.90 ± 16.18% [healthy]), followed by the gastrocnemius medialis (29.87 ± 10.67% [AT] < 32.19 ± 12.90% [healthy]) and the gastrocnemius lateralis (9.30 ± 4.31% [AT] < 10.91 ± 4.66% [healthy]). The triceps surae force-sharing strategy was different for the toe walking, heel walking, and the bilateral and unilateral heel drop with extended knee. This study provides evidence for altered triceps surae muscle force-sharing strategies during dynamic tasks in patients with AT. The influence of altered muscle force-sharing on the subtendon nonuniformity and/or the tendon loading should be explored in future work.

Increased muscle force does not induce greater stretch-induced damage to calf muscles during work-matched heel drop exercise

PurposeTo investigate the effect of muscle force during active stretch on quantitative and qualitative indicators of exercise-induced muscle damage (EIMD) in the medial gastrocnemius (MG) muscle.MethodsTwelve recreationally active volunteers performed two trials of an eccentric heel drop exercise. Participants performed a single bout of low-load (body weight) and high-load (body weight + 30% body weight) exercises on separate legs. The total mechanical work output for each condition was matched between legs. Before, two hours and 48 h after each bout of eccentric exercise, electrically stimulated triceps surae twitch torque, muscle soreness, MG active fascicle length at maximum twitch torque and muscle passive stiffness were collected. Triceps surae electromyographic (EMG) activity, MG fascicle stretch and MG muscle–tendon unit (MTU) length were measured during the eccentric tasks.ResultsThe high-load condition increased triceps surae muscle activity by 6–9%, but reduced MG fascicle stretch (p < 0.001). MTU stretch was similar between conditions. The greater muscle force during stretch did not give rise to additional torque loss (5 vs 6%) or intensify muscle soreness.ConclusionsAdding 30% body weight during eccentric contractions has a modest impact on exercise-induced muscle damage in the medial gastrocnemius muscle. These results suggest that muscle load may not be an important determinant of stretch-induced muscle damage in the human MG muscle. The muscle investigated does exhibit large pennation angles and high series elastic compliance; architectural features that likely buffer muscle fibres against stretch and damage.

SIMPLIFIED METHOD FOR PREDICTION OF VIBRATION BEHAVIOR OF STEEL-CONCRETE COMPOSITE FLOOR SUBJECTED TO GENERAL LOADING

Vibration serviceability problems have often been encountered in steel-concrete composite floors due to their long span and lightweight nature and have low damping depending on the occupancy. These are being used for various applications and hence are being subjected to different dynamic loads such as those due to human excitations and mechanical vibrations. Thus, it becomes necessary to predict the vibration behaviour at the design stage itself to avoid problematic floors. Previous researchers have extensively studied and presented simplified equations to understand the behaviour of floors subjected to human excitations such as walking, jumping, dancing, etc., but these equations are based on the beam mode of vibration. This paper presents a method that captures the behaviour of the floor alone subjected to a certain frequency and a general dynamic load. A novel displacement-controlled test to predict natural frequency was conducted in which the floor was subjected to vibration with a certain displacement over a range of forcing frequencies away from the natural frequency and the results conclude that the method shows good agreement with the traditional heel drop test and can be used for the purpose.

Subject-Specific 3D Models to Investigate the Influence of Rehabilitation Exercises and the Twisted Structure on Achilles Tendon Strains

The Achilles tendon (AT) is the largest tendon of the human body and has a primary role in locomotor activities. The complex structure of the AT includes twisting of three sub-tendons, non-uniform tissue deformations and differential triceps surae muscle forces. The main aim of this study was to investigate the impact of commonly used rehabilitation exercises (walking on heels, walking on toes, unilateral heel rise, heel drop with extended knee and heel drop with the knee bent) and different twists on AT strains. 3D freehand ultrasound based subject-specific geometry and subject-specific muscle forces during different types of rehabilitation exercises were used to determine tendon strains magnitudes and differences in strains between the sub-tendons. In addition, three Finite Element models were developed to investigate the impact of AT twist. While walking on heels developed the lowest average strain, heel drop with knee bent exhibited the highest average strain. The eccentric heel drop resulted in higher peak and average strain, compared to concentric heel rise for all the three models. The isolated exercises (heel rise and heel drop) presented higher average strains compared to the functional exercises (walking tasks). The amount of twist influences the peak strains but not the average. Type I consistently showed highest peak strains among the five rehabilitation exercises. The ranking of the exercises based on the AT strains was independent of AT twist. These findings might help clinicians to prescribe rehabilitation exercises for Achilles tendinopathy based on their impact on the AT strains.

A Cadaveric Study Addressing the Feasibility of Remote Patient Monitoring Prosthesis for Total Knee Arthroplasty.

Since the COVID-19 pandemic of 2020, there has been a marked rise in the use of telemedicine to evaluate patients after total knee arthroplasty (TKA). The purpose of our study was to assess a novel stem with an embedded sensor that can remotely and objectively monitor a patient's mobility after TKA. A single anatomically designed knee system was implanted in concert with an interconnected tibial stem extension containing 3D accelerometers, 3D gyroscopes, a power source, and a telemetry transmission capability in 3 cadaveric pelvis to toe specimens. The legs were moved by hand to preset tibial positions at full knee extension, midflexion, flexion, and back to midflexion and extension for a total of 16 trials across 6 knees. Sensor data were successfully transmitted with good quality of signal to an external base station. Good correlation to the range of motion of the tibia was found (mean error 0.1 degrees; root mean square error 3.8 degrees). The signal from the heel drop tests suggests the sensor could detect heel strike during activities of daily living invivo and the potential for additional signal processing to analyze vibratory and motion patterns detected by the sensors. A frequency domain analysis of a properly cemented and poorly cemented implant during the heel drop test suggests a difference in accelerometer signal in these implant states. The results confirm signals generated from an embedded TKA sensor can transmit through bone and cement, providing accurate range of motion data and may be capable of detecting changes in prosthesis fixation remotely.

Predicting Embodied Carbon and Cost Effectiveness of Post-Tensioned Slabs Using Novel Hybrid Firefly ANN

Post-tensioning has become a strong contender for manufacturing reinforced concrete (RC) members, especially for flat slabs in large-span structures. Post-tensioned (PT) slabs can lead to considerable material savings while reducing the embodied carbon (embodied CO2), construction time, and life cycle maintenance and repair costs. In this research, a novel hybrid Firefly–Artificial Neural Network (Firefly–ANN) computational intelligence model was developed to estimate the cost effectiveness and embodied CO2 of PT slabs with different design variables. To develop the dataset, several numerical models with various design variables, including the pattern of tendons, slab thickness, mechanical properties of materials, and span of slabs, were developed to investigate the sustainability and economic competitiveness of the derived designs compared to benchmark conventional RC flat slabs. Several performance measures, including punching shear and heel drop vibration induced by human activity, were used as design constraints to satisfy safety and serviceability criteria. The economic competitiveness of PT slabs was more evident in larger spans where the cost and embodied CO2 emissions decreased by 39% and 12%, respectively, in PT slabs with a 12-m span length compared to conventional RC slabs. Sensitivity analysis also confirmed that the cost and embodied CO2 emissions were very sensitive to the slab thickness by 86% and 62%, respectively.

Plantar pressure distribution and perceived comfort in hiking boots with different heel-to-toe drops before and after 45 minutes of walking

The purpose of this study was to investigate the influence of heel-to-toe drop (heel drop) modifications of a hiking shoe on plantar pressure distribution and perceived comfort before and after walking. Data of three shoe conditions with a low (11 mm), medium (16 mm) and high (21 mm) heel drop were obtained of twelve healthy male participants (mean age: 23.8 ± 2.8 yrs.) before (pre-test) and after a 45-minute walk in a park (post-test). Two-way repeated-measures analysis of variance (ANOVA) was applied to investigate differences between the three shoe types at the two time points and over time. Post-hoc analyses showed few significant differences in pressure and comfort parameters between shoe conditions at the two time points. Over time, however, several significant changes in comfort measures and pressure distribution were observed depending on the shoe condition. Most of the plantar pressure changes were seen in the hiking shoe with the medium heel drop showing significantly increased pressures values in the toe and forefoot area after the walk. Comfort measures deteriorated from the pre-to the post-test, in particular for the hiking shoe with the high heel drop. The results of the study showed that comfort and pressure parameters altered from walking for 45 minutes depending on the shoe condition and that the modification of the heel drop affected pressure parameters and comfort parameters in different ways. These findings may have implications for future considerations of values for the heel drop in hiking shoes.

Cyclic eccentric stretching induces more damage and improved subsequent protection than stretched isometric contractions in the lower limb.

Controversy remains about whether exercise-induced muscle damage (EIMD) and the subsequent repeated bout effect (RBE) are caused by the stretching of an activated muscle, or the production of high force at long, but constant, muscle lengths. The aim of this study was to determine the influence of muscle fascicle stretch elicited during different muscle contraction types on the magnitude of EIMD and the RBE. Fourteen participants performed an initial bout of lower limb exercise of the triceps surae. One leg performed sustained static contractions at a constant long muscle length (ISO), whereas the contralateral leg performed a bout of eccentric heel drop exercise (ECC). Time under tension was matched between the ECC and ISO conditions. Seven days later, both legs performed ECC. Plantar flexor twitch torque, medial gastrocnemius (MG) fascicle length and muscle soreness were assessed before, 2h and 2days after each exercise bout. MG fascicle length and triceps surae surface electromyography were examined across the bouts of exercise. We found that both ECC and ISO conditions elicited EIMD and a RBE. ISO caused less damage 2h after the initial bout (14% less drop in twitch torque, P = 0.03) and less protection from soreness 2days after the repeated bout (56% higher soreness, P = 0.01). No differences were found when comparing neuromechanical properties across exercise bouts. For MG, the action of stretching an active muscle seems to be more important for causing damage than a sustained contraction at a long length.

An eccentric ankle heel drop into dorsiflexion as opposed to neutral causes more Achilles tendon tissue displacement, but not more non‐uniformity

To evaluate whether an adapted exercise regimen changes the intratendinous behavior of the Achilles tendon, comparing 2 variations of mechanical loading exercises: (i) heel drop with dorsiflexion (DF) and (ii) heel drop without dorsiflexion (N). Nineteen participants, 11 men and 8 women, mean age of 28 years, were included in the study. An ultrasound-based speckle tracking technique was used to measure the mean local tendon tissue displacement of the different layers of the Achilles tendon during exercises DF and N. During acquisition, the edge of the calcaneus was always in sight at the outer edge of the image, leaving the rest of the image filled with pre-insertional Achilles tendon. All statistics were performed using SPSS. During DF, there was a significantly greater displacement of the Achilles tendon than during N: 3.46 mm vs 2.61mm (P < .05). The amount of non-uniformity, that is, the relative difference in displacement between tendon layers, between both groups (DF and N) showed no significant difference. Changing the exercise regimen in accordance to the location of the structural abnormalities in the Achilles tendon (eg, insertional vs midportion) may have better clinical outcomes in comparison with the “one size fits all” eccentric heel drop.

EFFICACY OF ULTRASOUND-GUIDED AUTOLOGOUS BLOOD INJECTION VERSUS EXTRACORPOREAL SHOCKWAVE THERAPY IN CHRONIC ACHILLES TENDINOPATHY: A RANDOMIZED CONTROLLED TRIAL

Objective:To evaluate the efcacy of ultrasound-guided autologous blood injection in chronic Achilles tendinopathy. Design: Prospective randomised controlled trial. Setting:Tertiary care hospital. Participants: 45 patients of chronic Achilles tendinopathy. Intervention: Participants were allocated to 2 groups i.e. autologous blood injection under ultrasound-guidance group (n=23) and extra corporeal shockwave therapy group (n=22) while in both groups eccentric heel drop stretching exercise were added. Outcome measures:VAS, VISA-Aand ultrasonography. Follow up at 4, 12 and 24 weeks. Results: The mean VAS score changes within-subject analysis were signicant in both ABI and ESWT group (p&lt;0.001), however between-group analysis at 4, 12 and 24 weeks were not signicant (p&gt;0.05). The mean VISA-A score within-subject analysis were signicant in both the groups (p&lt;0.001). The between-group analysis show signicant difference at 12 weeks (p=0.006) and 24 weeks (p=0.001). The between-group analysis of mean tendon size were signicant at 24 weeks (p=0.001). Conclusions: This study showed that ultrasound guided autologous blood injection is effective in reducing pain and disability in chronic Achilles tendinopathy at 6 months. ABI might have additive regenerative therapeutic effect.

A novel murine muscle loading model to investigate Achilles musculotendinous adaptation.

Achilles tendinopathy is a debilitating condition affecting the entire spectrum of society and a condition that increases the risk of tendon rupture. Effective therapies remain elusive, as anti-inflammatory drugs and surgical interventions show poor long-term outcomes. Eccentric loading of the Achilles muscle-tendon unit is an effective physical therapy for treatment of symptomatic human tendinopathy. Here, we introduce a novel mouse model of hindlimb muscle loading designed to achieve a tissue-targeted therapeutic exercise. This model includes the application of tissue (muscle and tendon)-loading "doses," coupled with ankle dorsiflexion and plantarflexion, inspired by human clinical protocols. Under computer control, the foot was rotated through the entire ankle joint range of motion while the plantar flexors simultaneously contracted to simulate body mass loading, consistent with human therapeutic exercises. This approach achieved two key components of the heel drop and raise movement: ankle range of motion coupled with body mass loading. Model development entailed the tuning of parameters such as footplate speed, number of repetitions, number of sets of repetitions, treatment frequency, treatment duration, and treatment timing. Initial model development was carried out on uninjured mice to define a protocol that was well tolerated and nondeleterious to tendon biomechanical function. When applied to a murine Achilles tendinopathy model, muscle loading led to a significant improvement in biomechanical outcome measures, with a decrease in cross-sectional area and an increase in material properties, compared with untreated animals. Our model facilitates the future investigation of mechanisms whereby rehabilitative muscle loading promotes healing of Achilles tendon injuries.NEW & NOTEWORTHY We introduce a novel mouse model of hindlimb muscle loading designed to achieve a tissue-targeted therapeutic exercise. This innovative model allows for application of muscle loading "doses," coupled with ankle dorsiflexion and plantarflexion, inspired by human loading clinical treatment. Our model facilitates future investigation of mechanisms whereby rehabilitative muscle loading promotes healing of Achilles tendon injuries.

Targeted Achilles Tendon Training and Rehabilitation Using Personalized and Real-Time Multiscale Models of the Neuromusculoskeletal System.

Musculoskeletal tissues, including tendons, are sensitive to their mechanical environment, with both excessive and insufficient loading resulting in reduced tissue strength. Tendons appear to be particularly sensitive to mechanical strain magnitude, and there appears to be an optimal range of tendon strain that results in the greatest positive tendon adaptation. At present, there are no tools that allow localized tendon strain to be measured or estimated in training or a clinical environment. In this paper, we first review the current literature regarding Achilles tendon adaptation, providing an overview of the individual technologies that so far have been used in isolation to understand in vivo Achilles tendon mechanics, including 3D tendon imaging, motion capture, personalized neuromusculoskeletal rigid body models, and finite element models. We then describe how these technologies can be integrated in a novel framework to provide real-time feedback of localized Achilles tendon strain during dynamic motor tasks. In a proof of concept application, Achilles tendon localized strains were calculated in real-time for a single subject during walking, single leg hopping, and eccentric heel drop. Data was processed at 250 Hz and streamed on a smartphone for visualization. Achilles tendon peak localized strains ranged from ∼3 to ∼11% for walking, ∼5 to ∼15% during single leg hop, and ∼2 to ∼9% during single eccentric leg heel drop, overall showing large strain variation within the tendon. Our integrated framework connects, across size scales, knowledge from isolated tendons and whole-body biomechanics, and offers a new approach to Achilles tendon rehabilitation and training. A key feature is personalization of model components, such as tendon geometry, material properties, muscle geometry, muscle-tendon paths, moment arms, muscle activation, and movement patterns, all of which have the potential to affect tendon strain estimates. Model personalization is important because tendon strain can differ substantially between individuals performing the same exercise due to inter-individual differences in these model components.

Vibration testing for dynamic properties of building floors

The paper presents a comparison of testing methods and post processing techniques for modal properties of a fully furnished chipboard floor and an unfurnished prestressed concrete floor. A thorough modal testing required relocation of transducers among test setups to acquire multiple synchronous measurements of floor response due to heel drop excitation or shaker excitation. The comprehensive experimental data was processed by a specialised operational modal analysis software. On the other hand, a simple testing approach only required records of floor response at a single point due to heel drop. The measured response can be easily analyzed using simple procedures of structural dynamics. Whilst valuable information about the floor modal properties including the mode shapes was obtained using the sophisticated approach, the uncomplicated single-point heel drop test was found to provide reasonably accurate evaluation of natural frequencies and damping ratios for both of the test floors, which verifies the attractiveness of the simple technique. Based on experimental results, both of the floors would be considered as low-frequency floors by commonly used guidelines on human-induced floor vibrations. Furthermore, the effect of fit-out conditions and construction materials on the huge discrepancy between damping values of the two floors was also observed.

An investigation of human comfort criteria for footfall induced floor vibrations

Human comfort is becoming a vital serviceability requirement when it comes to design of long-span floor systems, as evidenced by the development of international standards on human exposure to vibrations. This paper discusses experimental findings derived from dynamic testing of a real office floor of steel-concrete composite construction where annoying footfall-induced vibration had been reported by the floor tenants. The fundamental frequency of the problematic floor was determined using measurements obtained from a series of simple heel drop tests. The observed vibration levels of the floor under normal walking excitations was then benchmarked against acceptance criteria suggested by a number of widely used floor vibration design guides. From a human comfort perspective, it is found that the same floor can be classified as unacceptable by some guidelines but deemed extremely acceptable by the others. As response levels are translated inconsistently by various acceptance criteria, designers would hence be placed in a dilemma when deciding whether the existing floor really needs modification to enhance its serviceability.

Experimental investigation of the low-frequency impact sound transfer function of lightweight wooden floors via heel drops

The lightweight floor is a popular construction choice in buildings despite its poor low-frequency impact sound performance. This is exacerbated by common human activities, such as walking and jumping, that have high input force levels at low frequencies. Therefore, experimental evaluations of the low-frequency impact sound performance of a wooden lightweight floor are of interest to designers and researchers. The aim of this paper is to explore the use of heel drop for impact sound transfer measurement. An impact force plate has been built to accurately measure the heel-drop forces up to 200 Hz and the performances on two types of floors are evaluated. The heel drop has a higher energy level at low frequencies, resulting in higher coherence and signal-to-noise ratio and hence superior performance in characterizing the floors in the frequency range of below 40 Hz when compared to the impact hammer. Interestingly, in the case of a heel-drop excitation, the first natural frequencies of the floor decrease. It is in contrast to when a human is simply standing on it, which resulted in an increase of the natural frequencies upon impact hammer excitation.

Effects of the Functional Heel Drop Exercise on the Muscle Architecture of the Gastrocnemius.

The architectural characteristics of a muscle determine its function. To determine the architectural adaptations of the lateral gastrocnemius (LG) and medial gastrocnemius (MG) muscles after a functional eccentric strength training protocol consisting of heel drop exercises, followed by a subsequent detraining period. Pretest and posttest. Training rooms and laboratory. The participants (N = 45) who were randomly divided into an experimental group (EG, n = 25) and a control group (CG, n = 20). The 13-week intervention included participants (N = 45) who were randomly divided into an EG (n = 25) and a CG (n = 20). The EG performed a week of control and training, 8 weeks of eccentric training, and 4 weeks of detraining. The CG did not perform any type of muscular training. The architectural characteristics of the LG and MG muscles were evaluated at rest in both groups using 2-D ultrasound before (pretest-week 1) and after (posttest-week 9) the training, and at the end of the detraining period (retest-week 13). One-way repeated measures analysis of variance was used to determine training-induced changes in each of the variables of the muscle architecture. After the training period, the members of the EG experienced a significant increase in the fascicle length of LG (t = -9.85, d = 2.78, P < .001) and MG (t = -8.98, d = 2.54, P < .001), muscle thickness (t = -6.71, d = 2.86, P < .001) and (t = -7.85, d = 2.22, P < .001), and the pennation angle (t = -10.21, d = 1.88, P < .05) and (t = -1.87, d = 0.53, P < .05), respectively. After the detraining period, fascicle length, muscle thickness, and pennation angle showed a significant decrease. In the CG, no significant changes were observed in any of the variables. The heel drop exercise seems to generate adaptations in the architectural conditions of LG and MG, which are also reversible after a detraining period. These results may have practical implications for injury prevention and rehabilitation programs.

Influence of speed and heel-to-toe drop in running shoes for female recreational runners

In recent years, the popularity of running has boomed and the number of women runners has risen sharply. However, little research has been conducted into the running cycle as concerns female runners. The aim of this study is to analyse, in women runners, the relationships between spatiotemporal parameters in the running cycle, the heel drop in running shoes and a progressive increase in training speed, when running on a treadmill.Thirty-eight female runners were recruited from the Malaga University Athletics Club and Nerja Athletics Club. All were at least 18 years old, recreationally active (3–4 running sessions per week) and able to run 5 km in less than 25 min. Their running performance on a treadmill was recorded and spatiotemporal parameters assessed using the OptoGait system.As the running speed increased (8–12–15 km/h) the spatiotemporal parameters of the running cycle altered: the flight time increased (P < .001) and the contact time decreased (P = .05). Heel drop (4–12 mm) was not significantly associated with any of the parameters (phase 1: P = .198; phase 2: P = .191; phase 3: P = .242).A progressive increase in training speed on a treadmill directly influences the spatiotemporal parameters of the running cycle in women runners.