Achilles tendon dimensions, ankle stiffness and footfall patterns in recreational runners.

The main purpose of this study was to investigate the relationship among Achilles tendon (AT) dimensions, ankle joint stiffness, and footfall patterns in recreational rearfoot and non-rearfoot runners. Based on the foot strike index, a total of 107 runners were divided into rearfoot (47 females/40 males) and non-rearfoot runners (14 females/6 males). All participants had theirs AT dimensions (AT length, AT thickness, and AT moment arm) measured using a combination of ultrasound and motion capture systems. In addition, all performed running trials measured at self-selected speed in laboratory-neutral shoes. A partial correlation coefficient was used for correlations between the selected variables. The results revealed a significant relationship between ankle joint stiffness and level of footfall pattern in rearfoot (r = 0.232, p = 0.032) and non-rearfoot runners (r = -0.811, p < 0.001). The results also suggest a relationship between AT thickness and foot strike index (r = -0.486) in non-rearfoot runners. Runners whose footfall pattern is closer to the heel have greater ankle joint stiffness. Non-rearfoot runners whose footfall pattern is closer to the toe have a thinner AT. Non-rearfoot runners with thicker AT had greater ankle joint stiffness.

Achilles tendon structure is associated with regular running volume and biomechanics.

Achilles tendinopathy was reported to have the highest incidence proportion of all running-related injuries. The purpose of this study was to analyse the association between the Achilles tendon structure and running activity status. 350 healthy participants (runners and inactive controls, 30-50 years) participated in this research. Each participant completed questionnaires: socioeconomic, psychological, physical activity habits, running status and history and VISA-A. Magnetic resonance imaging, anthropological, running biomechanics and 14 days of physical activity monitoring assessments were performed. There was a higher odd of being in the upper quartile of the Achilles tendon T2* relaxation time with higher maximal knee extension moment independent of age and sex. Compared with runners who ran 21-40 km per week, non-runners and those who ran more than 40 km per week had increased odds of having longest the Achilles tendon T2* relaxation time. Regular running of 21 to 40 km per week is related to the Achilles tendon T2* relaxation time indicating possibly better water content and collagen orientation in these runners with compare to inactive non-runners or highly active individuals. In addition, Achilles tendon T2* relaxation time as indirect indicator of the Achilles tendon structure was positively related to the maximal knee extension moment during running.

Running-Related Achilles Tendon Injury: A Prospective Biomechanical Study in Recreational Runners.

There are relatively few running studies that have attempted to prospectively identify biomechanical risk factors associated with Achilles tendon (AT) injuries. Therefore, the aim was to prospectively determine potential running biomechanical risk factors associated with the development of AT injuries in recreational, healthy runners. At study entry, 108 participants completed a set of questionnaires. They underwent an analysis of their running biomechanics at self-selected running speed. The incidence of AT running-related injuries (RRI) was assessed after 1-year using a weekly questionnaire standardized for RRI. Potential biomechanical risk factors for the development of AT RRI injury were identified using multivariable logistic regression. Of the 103 participants, 25% of the sample (15 males and 11 females) reported an AT RRI on the right lower limb during the 1-year evaluation period. A more flexed knee at initial contact (odds ratio = 1.146, P = .034) and at the midstance phase (odds ratio = 1.143, P = .037) were significant predictors for developing AT RRI. The results suggested that a 1-degree increase in knee flexion at initial contact and midstance was associated with a 15% increase in the risk of an AT RRI, thus causing a limitation of training or a stoppage of running in runners.

Age differences in running biomechanics during footstrike between preschool children and adults.

This study aimed to compare impact loading between two age groups of preschool children (3-4 and 5-6 years old) and one group of young adults representing mature level of running skill (n = 15 per group). Three-dimensional biomechanical data were collected during running barefoot, in minimalist and running shoes. A two-way mixed ANOVA was performed to assess age and footwear differences in vertical instantaneous loading rate (VILR). An interaction was found in VILR. Older (5-6) preschoolers had 30-31% lower VILR than younger (3-4) (p = 0.012, d = 1.02; p = 0.001, d = 1.18) and adults had 51-77% lower VILR than younger preschoolers (p = 0.001, d = 1.85; p = 0.001, d = 2.82) in minimalist and running shoes, respectively. Additionally, adults had lower VILR than older preschoolers in running shoes (p = 0.001, d = 2.68). No differences were found between older children and adults in barefoot and minimalist shoes. Loading decreased with increasing age, particularly in minimalist and running shoes. Unchanged cadence and running speed did not explain the decrease of VILR during preschool age. The explanation likely underlies in lower limb alignment during footstrike and developmental ontogenetic changes.

Does the Achilles Tendon Influence Foot Strike Patterns During an Exhaustive Run?

The study purpose was to investigate whether there is a relationship between the Achilles tendon (AT) length, moment arm length, and the foot strike pattern (FP) change during an exhaustive run (EXR) in nonrearfoot FP runners. Twenty-eight runners were recruited and divided into 2 groups (highly trained/moderately trained) according to their weekly training volume. Participants underwent the graded exercise test, the EXR with biomechanical analysis at the beginning, and at the end, and the magnetic resonance imaging scan of the AT. Correlations were used to assess associations between FP change (value of the difference between end and beginning) and the selected performance and AT variables. AT length significantly correlated with the FP change according to foot strike angle (r = -.265, P = .049). The AT moment arm length significantly correlated with the FP change according to strike index during EXR (r = -.536, P = .003). Multiple regression showed that AT length was a significant predictor for the FP change according to foot strike angle if the second predictor was the graded exercise test duration and the third predictor was training group association. These results suggest that a runner's training volume, along with a longer AT and AT moment arm appear to be associated with the ability to maintain a consistent FP during EXR by nonrearfoot FP runners.

Marker Placement Reliability and Objectivity for Biomechanical Cohort Study: Healthy Aging in Industrial Environment (HAIE-Program 4).

In large cohort studies, due to the time-consuming nature of the measurement of movement biomechanics, more than one evaluator needs to be involved. This may increase the potential occurrence of error due to inaccurate positioning of markers to the anatomical locations. The purpose of this study was to determine the reliability and objectivity of lower limb segments length by multiple evaluators in a large cohort study concerning healthy aging in an industrial environment. A total of eight evaluators performed marker placements on five participants on three different days. Evaluators placed markers bilaterally on specific anatomical locations of the pelvis, thigh, shank and foot. On the right foot, markers were placed in anatomical locations to define a multi-segmental foot model. The position of the marker at the anatomical locations was recorded by a motion capture system. The reliability and objectivity of lower limb segment lengths was determined by the intraclass correlation coefficient of a two-way random model and of the two-way mixed model, respectively. For all evaluators for all segments, the average reliability and objectivity was greater than 0.8, except for the metatarsus segment (0.683). Based on these results, we can conclude that multiple evaluators can be engaged in a large cohort study in the placement of anatomical markers.

Associated ACL risk factors differences during an unanticipated volleyball blocking movement.

The lateral tilt of the arms accompanied by trunk lateral tilt is a typical blocking manoeuvre in volleyball. However, during this unanticipated blocking movement, an associated risk of ACL injury may result. The aim of the present study was to compare associative ACL risk factors at the initial contact and the first and second peak of VGRF during an unanticipated blocking movement with different arm positions. Synchronized kinematic and kinetic data were collected for each trial of each condition. Student paired t-tests and effect size were used to determine differences between two conditions (S - with arms straight up from the body) and (T - with the arms and trunk laterally tilted). The results showed that the T condition significantly decreases knee flexion, increases VGRF at the foot contact, first peak force and increases the valgus moment at the first peak force. The values of the associated risk factors for a non-contact ACL injury appear to be related to the tilted arm position accompanied by trunk tilt towards to right lower limb during landing. The players should be taught to land with greater knee flexion and, if possible, a double-leg landing to decrease right lower limb loading during the blocking manoeuvre.

Reliability of a measurement technique for achilles tendon length.

Recently, there has been an increasing amount of literature dealing with new methods of Achilles tendon (AT) length measurement. However, most of these studies measured the AT length between the calcaneus and medial head of the gastrocnemius and the reliability of such a measurement has not been satisfactorily presented. The purpose of this study was to determine the reliability of the measurement of AT length within and between sessions. AT length was measured by using a combination of ultrasound imaging and optoelectronic stereophotogrammetry. Nineteen healthy athletes visited the lab on six different days where the AT length was measured on both lower extremities: 1) from the calcaneus to the mid-point of the medial and lateral heads of the gastrocnemius; and 2) from the calcaneus to the soleus musculotendinous attachment. The reliability results indicated high intraclass correlation coefficients (ICC > 0.8), a low typical error (< 0.6) and a standard error of measurement (SEM < 5.5 mm) for all measured AT lengths on within and between sessions. This non-invasive reliable measurement method may be recommended for sport science research purposes.

Blocking landing techniques in volleyball and the possible association with anterior cruciate ligament injury.

The number and type of landings performed after blocking during volleyball matches has been related to the potential risk of ACL injury. The aim of the present study was to determine whether gender affects the frequency of specific blocking landing techniques with potential risk of ACL injury from the perspective of foot contact and subsequent movement after the block used by volleyball players during competitive matches. Three matches involving four female volleyball teams (fourteen sets) and three matches involving four male volleyball teams (thirteen sets) in the Czech Republic were analyzed for this study. A Pearson chi-square test of independence was used to detect the relationship between gender and different blocking techniques. The results of the present study showed that gender affected single-leg landings with subsequent movement in lateral direction and double-leg landings. Although the total number of landings was lower for male athletes than for female athletes, a larger portion of male athletes demonstrated single leg landings with a subsequent movement than female athletes. Single leg landings with a subsequent movement have a higher potential risk of ACL injury.

The influence of hand positions on biomechanical injury risk factors at the wrist joint during the round-off skills in female gymnastics.

The aim of this study was to examine the biomechanical injury risk factors at the wrist, including joint kinetics, kinematics and stiffness in the first and second contact limb for parallel and T-shape round-off (RO) techniques. Seven international-level female gymnasts performed 10 trials of the RO to back handspring with parallel and T-shape hand positions. Synchronised kinematic (3D motion analysis system; 247 Hz) and kinetic (two force plates; 1235 Hz) data were collected for each trial. A two-way repeated measure analysis of variance (ANOVA) assessed differences in the kinematic and kinetic parameters between the techniques for each contact limb. The main findings highlighted that in both the RO techniques, the second contact limb wrist joint is exposed to higher mechanical loads than the first contact limb demonstrated by increased axial compression force and loading rate. In the parallel technique, the second contact limb wrist joint is exposed to higher axial compression load. Differences between wrist joint kinetics highlight that the T-shape technique may potentially lead to reducing these bio-physical loads and consequently protect the second contact limb wrist joint from overload and biological failure. Highlighting the biomechanical risk factors facilitates the process of technique selection making more objective and safe.

Segment coupling and coordination variability analyses of the roundhouse kick in taekwondo relative to the initial stance position.

The initial stance position (ISP) has been observed as a factor affecting the execution technique during taekwondo kicks. In the present study, authors aimed to analyse a roundhouse kick to the chest by measuring movement coordination and the variability of coordination and comparing this across the different ISP (0°, 45° and 90°). Eight experienced taekwondo athletes performed consecutive kicking trials in random order from every of the three relative positions. The execution was divided into three phases (stance, first swing and second swing phase). A motion capture system was used to measure athletes' angular displacement of pelvis and thigh. A modified vector coding technique was used to quantify the coordination of the segments which contributed to the overall movement. The variability of this coordination (CV) for each ISP was also calculated. Comparative analysis showed that during the stance phase in the transverse plane, athletes coordinated movement of the trunk and thigh with a higher frequency of in-phase and lower frequency of exclusive thigh rotation in the 0° stance than the 90° stance position (P < 0.05). CV was also influenced by the different ISP. During the first swing and the majority of the second swing phase, predominant in-phase coordination of the pelvis and thigh was observed. Including exercises that require in-phase movement could not only help athletes to acquire coordination stability but also efficiency. The existence of a constraint such as ISP implies an increase of the variability when the athletes have to kick from ISP they are not used to adopt (i.e., 0° and 90° ISP) as an evidence of adaptability in the athletes' execution technique.

Lower extremity power during the squat jump with various barbell loads.

The purpose of this study was twofold: (1) to determine the barbell load that maximised the system power as well as the ankle, knee, and hip joint powers during the squat jump, and (2) to compare the system powers computed from two different methods: the centre of mass (COM) method and the barbell method. Seven male throwers were recruited in this study. The system power (COM method) and the ankle, knee, and hip joint powers were determined with the load incrementally set at 0%, 10%, 30%, 50%, 70%, and 90% of one repetition maximum. The largest system power was observed at the load of 30% (p < 0.008) while the largest ankle and knee powers were observed at 70% and 0% (p < 0.05). The barbell method overestimated the system power (p < 0.001) when compared to the COM method. It was concluded that the barbell method could influence load optimisation in squat jump. The optimal barbell load which maximised the system power did not maximise the ankle, knee, or hip power simultaneously.

Musculoskeletal loading during the round-off in female gymnastics: the effect of hand position.

Chronic elbow injuries from tumbling in female gymnastics present a serious problem for performers. This research examined how the biomechanical characteristics of impact loading and elbow kinematics and kinetics change as a function of technique selection. Seven international-level female gymnasts performed 10 trials of the round-off from a hurdle step to flic-flac with 'parallel' and 'T-shape' hand positions. Synchronized kinematic (3D-automated motion analysis system; 247 Hz) and kinetic (two force plates; 1,235 Hz) data were collected for each trial. Wilcoxon non-parametric test and effect-size statistics determined differences between the hand positions examined in this study. Significant differences (p < 0.05) and large effect sizes (ES > 0.8) were observed for peak vertical ground reaction force (GRF), anterior-posterior GRF, resultant GRF, loading rates of these forces and elbow joint angles, and internal moments of force in sagittal, transverse, and frontal planes. In conclusion, the T-shape hand position reduces vertical, anterior-posterior, and resultant contact forces and has a decreased loading rate indicating a safer technique for the round-off. Significant differences observed in joint elbow moments highlighted that the T-shape position may prevent overloading of the joint complex and consequently reduce the potential for elbow injury.

Comparison of bone mineral density of runners with inactive males: A cross-sectional 4HAIE study.

The purpose of the study was to determine whether running is associated with greater bone mineral density (BMD) by comparing the BMD of regularly active male runners (AR) with inactive nonrunner male controls (INC). This cross-sectional study recruited 327 male AR and 212 male INC (aged 18-65) via a stratified recruitment strategy. BMD of the whole body (WB) and partial segments (spine, lumbar spine (LS), leg, hip, femoral neck (FN), and arm for each side) were measured by dual-energy x-ray absorptiometry (DXA) and lower leg dominance (dominant-D/nondominant-ND) was established by functional testing. An ANCOVA was used to compare AR and INC. The AR had greater BMD for all segments of the lower limb (p<0.05), but similar BMD for all segments of the upper limb (p>0.05) compared with INC. Based on the pairwise comparison of age groups, AR had greater BMD of the ND leg in every age group compared with INC (p<0.05). AR had grater BMD of the D leg in every age group except for (26-35 and 56-65) compare with INC (p<0.05). In the youngest age group (18-25), AR had greater BMD in every measured part of lower extremities (legs, hips, femoral necks) compared with INC (p<0.05). In the 46-55 age group AR had greater BMD than INC (p < 0.05) only in the WB, D Leg, D neck, and ND leg. In the 56-65 age group AR had greater BMD than INC (p<0.05) only in the ND leg. Overall, AR had greater BMD compared with INC in all examined sites except for the upper limbs, supporting the notion that running may positively affect bone parameters. However, the benefits differ in the skeletal sites specifically, as the legs had the highest BMD difference between AR and INC. Moreover, the increase in BMD from running decreased with age.

Physical activity and menopausal symptoms: evaluating the contribution of obesity, fitness, and ambient air pollution status.

OBJECTIVE: The menopausal transition is accompanied by transient symptoms that have been linked to subclinical cardiovascular disease (CVD); CVD has also been linked to air pollution. Physical activity (PA) reduces CVD, improves body composition, and can reduce menopausal symptoms. The purpose of this study was to assess the links between PA and menopausal symptoms and whether obesity, fitness, and air pollution status play a role in this relationship. METHODS: Women (40-60 y; N = 243; mean [SD] age, 47.8 [5.6] y) from areas with high versus low air pollution enrolled in the Healthy Aging in Industrial Environment Program 4 prospective cohort study completed psychological, cardiorespiratory fitness, body composition, and menopausal status screening followed by a 14-day prospective assessment of menopausal symptoms (Menopause Rating Scale) using a mobile application. Daily PA was assessed objectively across 14 days via Fitbit Charge 3 monitor. General linear mixed models were conducted and controlled for age, menopausal status, day in the study, wear time, and neuroticism. RESULTS: Peri/postmenopausal women ( ß = 0.43, P < 0.001) and those residing in a high-air-pollution environment ( ß = 0.45, P < 0.05) reported more somatovegetative symptoms. Hot flashes alone were associated with peri/postmenopausal status ( ß = 0.45, P < 0.001), and for women residing in a high-air-pollution environment, lower reporting of hot flashes was observed on days when a woman was more physically active than usual ( ß = -0.15, P < 0.001). No associations were found for cardiorespiratory fitness and visceral fat with any of the symptoms. CONCLUSIONS: PA may enhance resilience to hot flashes, especially when residing in high-air-pollution environments where we also observed higher reporting of somatovegetative menopausal symptoms.

Air pollution, cardiorespiratory fitness and biomarkers of oxidative status and inflammation in the 4HAIE study.

The aim of this study was to investigate the associations between cardiorespiratory fitness (CRF), long-term air pollution exposure and biochemical markers of oxidative status and inflammation. This is a cross-sectional investigation focusing on biochemical markers of oxidative status and inflammation. Participants were Caucasian (N = 1188; age 18-65 years) who lived for at least 5 years in a high air-polluted (Moravian-Silesian; MS) or low air-polluted (South Bohemia; SB) region of the Czech Republic. Healthy runners and inactive individuals were recruited. A multiple regression analysis was used to explain the relationship between multiple independent variables (CRF, trunk fat mass, sex, socioeconomic status, and region (MS region vs. SB region) and dependent variables (oxidative status, inflammation). CRF, trunk fat mass, age and sex significantly predicted almost all selected markers of oxidative status and inflammation (except GSSG, GSH/GSSG and BDNF). Participants living in the MS region presented significantly higher GPx (by 3.1%) and lower BDNF values (by 4.5%). All other investigated biochemical markers were not significantly influenced by region. We did not find meaningful interactions between long-term air-pollution exposure versus markers of oxidative status and inflammation. However, we showed various significant interactions with sex, age, CRF and body composition. The significant association of living in the high air polluted MS region with the BDNF level warrants further attention.

The effect of regular running on the bone tissue of middle-aged men and women.

BACKGROUND: Many authors consider running to be a protective physical activity (PA) in bone health. However, many studies also show inconsistencies in their results. The objective of the study is to analyze the effect of cumulative loading rate (TCL) on the bone mass of middle-aged runners and non-runners is assessed. METHODS: This cross-sectional study included 322 individuals. There were 212 runners (109 male, 103 female) and those were individuals who did >10 km of running per week. There were 110 non-runners (54 male, 56 female). This group included individuals who did not adhere to the WHO (2020) recommendations for PA. The average age in the individual groups ranged from 40.9±4.1 to 42.3±4.8 years. Bone parameters were measured on the lower extremities and vertebral spine using the DXA method (Hologic QDR Horizon A). Multi-regression dependencies analysis was used to assess the results. RESULTS: The results of the multi-regression dependencies analysis showed that the bone mineral content (BMC) and bone mineral density (BMD) are significantly influenced by the TCL and gender. CONCLUSIONS: Therefore, we can conclude that running could be a suitable PA for preventing the reduction of BMD in the middle-aged population, especially in the lower limbs.

Regular Running Is Related to the Knee Joint Cartilage Structure in Healthy Adults.

PURPOSE: The purpose of this study was to determine whether regular running distance and biomechanics are related to medial central femur cartilage (MCFC) structure. METHODS: The cross-sectional study sample consisted of 1164 runners and nonrunners aged 18-65 yr. Participants completed questionnaires on physical activity and their running history. We performed quantitative magnetic resonance imaging of knee cartilage-T2 relaxation time (T2) mapping (high T2 indicates cartilage degeneration)-and a running biomechanical analysis using a three-dimensional motion capture system. A 14-d monitoring of the physical activity was conducted. RESULTS: Those aged 35-49 yr were at 84% higher odds of having MCFC T2 in the highest level (85th percentile, P < 0.05) compared with youngest adults indicating that MCFC structures may be altered with aging. Being male was associated with 34% lower odds of having T2 at the highest level ( P < 0.05) compared with females. Nonrunners and runners with the highest weekly running distance were more likely to have a high T2 compared with runners with running distance of 6-20 km·wk -1 ( P < 0.05). In addition, the maximal knee internal adduction moment was associated with a 19% lower odds of having T2 at the highest level ( P < 0.05). CONCLUSIONS: Females compared with males and a middle-aged cohort compared with the younger cohort seemed to be associated with the degeneration of MCFC structures. Runners who ran 6-20 km·wk -1 were associated with a higher quality of their MCFC compared with highly active individuals and nonrunners. Knee frontal plane biomechanics was related to MCFC structure indicating a possibility of modifying the medial knee collagen fibril network through regular running.

Effect of stance position on kick performance in taekwondo.

In taekwondo, the stance position can potentially affect kick performance. The aim of this study was to analyse mechanical variables in the roundhouse kick in taekwondo according to three stance positions (0°, 45°, 90°). Nine experienced taekwondo athletes performed consecutive kicking trials in a random order according to these three relative positions of the feet on the ground. Measurements for the mechanical analysis were performed using two 3D force plates and an eight-camera motion capture system. The taekwondo athletes' reaction and execution times were shorter when starting from the 0° and 45° stance positions than from the 90° position (P < 0.05). Moreover, the ground reaction force was negatively correlated with execution time and positively with velocity of thigh and shank. Our results suggest that the stance position affects the execution technique of taekwondo athletes' kicks. It is suggested that athletes should not adopt the 90° stance position because it will not enable them to achieve the best performance in the roundhouse kick.

Correlations between Achilles tendon material and structural properties and quantitative magnetic resonance imagining in different athletic populations.

Achilles tendon stiffness (kAT) and Young's modulus (yAT) are important determinants of tendon function. However, their evaluation requires sophisticated equipment and time-consuming procedures. The goal of this study was twofold: to compare kAT and yAT between populations using the classical approach proposed in the literature (a combination of ultrasound and force data) and the MRI technique to understand the MRI's capability in determining differences in kAT and yAT. Furthermore, we investigated potential correlations between short and long T2* relaxation time, kAT and yAT to determine whether T2* relaxation time may be associated with material or structural properties. Twelve endurance and power athlete, and twelve healthy controls were recruited. AT T2* short and long components were measured using standard gradient echo MRI at rest, while kAT and yAT were evaluated using the classical method (combination of ultrasound and dynamometric measurements). Power athletes had the highest kAT (3064 ± 260, 2714 ± 260 and 2238 ± 189 N/mm for power athletes, endurance athletes and healthy control, respectively) and yAT (2.39 ± 0.28, 1.64 ± 0.22 and 1.97 ± 0.32 GPa for power athletes, endurance athletes and healthy control, respectively) and the lowest T2* short component (0.58 ± 0.07, 0.77 ± 0.06 and 0.74 ± 0.08 ms for power athletes, endurance athletes and healthy control, respectively). Endurance athletes had the highest T2* long component value. No correlations were reported between T2* long component, kAT or yAT in the investigated populations, whereas the T2* short component was negatively correlated with yAT. These results suggest that T2* short component could be used to investigate the differences in AT material properties in different populations.