TY - JOUR A1 - Lesinski, Melanie A1 - Prieske, Olaf A1 - Chaabene, Helmi A1 - Granacher, Urs T1 - Seasonal effects of strength endurance vs. power training in young female soccer athletes JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - Lesinski, M, Prieske, O, Chaabene, H, and Granacher, U. Seasonal effects of strength endurance vs. power training in young female soccer athletes. J Strength Cond Res 35(12S): S90-S96, 2021-This study examined the seasonal effects of strength endurance training (SET) vs. power training (PT) on physical fitness and body composition in young female soccer players. Thirty-six young female elite soccer players (15 +/- 1 years; maturity offset +3 +/- 1 years) were allocated to progressive SET (n = 19) or PT (n = 17). Over the course of one soccer season, SET performed slow movement velocity, moderate intensity (50-60% of the 1 repetition maximum [1RM]; 20-40 repetitions) strength exercises while PT performed moderate-to-high intensity (50-95% of the 1RM; 3-8 repetitions), high movement velocity strength exercises (2 sessions center dot wk(-1)). Before and after training, tests were performed for the assessment of muscle strength (1RM leg press), jump performance (countermovement jump [CMJ], drop jump [DJ]), muscular endurance (ventral Bourban test), linear speed (10 m, 20 m), change-of-direction (CoD) speed (T-test), dynamic balance (Y-balance test), sport-specific performance (kicking velocity), and body composition (lean body mass and fat mass). An analysis of covariance was used to test for between-group differences at post-test with baseline values as covariate. No significant between-group differences were observed in terms of total training volume over the respective soccer seasons (p = 0.069; d = 0.68). At post-test, SET showed significantly better ventral Bourban and T-test performances (d = 1.28-2.28; p = 0.000-0.001) compared with PT. However, PT resulted in significantly better 1RM leg press, DJ, 10-m, and 20-m sprint performances (d = 0.85-1.44; p = 0.000-0.026). No significant between-group differences were observed at post-test for CMJ, Y-balance test, kicking performance, and body composition (d = 0.20-0.74, p = 0.051-0.594). Our findings are mainly in accordance with the principle of training specificity. Both SET and PT are recommended to be implemented in young female elite soccer players according to the respective training period. KW - strength training KW - elite KW - training specificity KW - soccer players KW - muscle KW - endurance KW - periodization Y1 - 2021 U6 - https://doi.org/10.1519/JSC.0000000000003564 SN - 1064-8011 SN - 1533-4287 VL - 35 IS - Supplement 12 SP - S90 EP - S96 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Jafarnezhadgero, Amir Ali A1 - Anvari, Maryam A1 - Granacher, Urs T1 - Long-term effects of shoe mileage on ground reaction forces and lower limb muscle activities during walking in individuals with genu varus JF - Clinical biomechanics N2 - Background: Shoe mileage is an important factor that may influence the risk of sustaining injuries during walking. The aims of this study were to examine the effects of shoe mileage on ground reaction forces and activity of lower limb muscles during walking in genu varus individuals compared with controls. Methods: Fifteen healthy and 15 genu varus females received a new pair of running shoes. They were asked to wear these shoes over 6 months. Pre and post intervention, mechanical shoe testing was conducted and ground reaction forces and muscle activities of the right leg were recorded during walking at preferred gait speed. Findings: Significant group-by-time interactions were found for shoe stiffness, antero-posterior and vertical impact peak. We observed higher shoe stiffness and lower impact peaks after intervention in both groups with larger effect sizes in genu varus. Significant group-by-time interactions were identified for vastus medialis (loading phase) and rectus femoris (loading and push-off). For vastus medialis, significant decreases were found from pre-to-post during the loading phase in the control group. Rectus femoris activity was higher post intervention during the loading and push-off phases in both groups with larger effect sizes in genu varus. Interpretation: Our findings indicate that the observed changes in ground reaction forces are more prominent in genu varus individuals. Together with our findings on shoe stiffness, it seems appropriate to change running shoes after an intense wearing time of 6 months, particularly in genu varus individuals. KW - footwear KW - electromyography KW - loading rate KW - patients Y1 - 2020 U6 - https://doi.org/10.1016/j.clinbiomech.2020.01.006 SN - 0268-0033 SN - 1879-1271 VL - 73 SP - 55 EP - 62 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Davies, Michael J. A1 - Drury, Benjamin A1 - Ramirez-Campillo, Rodrigo A1 - Chaabene, Helmi A1 - Moran, Jason T1 - Effect of plyometric training and biological maturation on jump and change of direction ability in female youth JF - Journal of strength and conditioning research : the research journal of the NSCA / National Strength & Conditioning Association N2 - Biological maturation has been shown to affect male youths' responses to plyometric training (PT). However, to date, no researcher has examined the effect of maturation on the effects of PT in female youth. We undertook the first controlled intervention study to examine this, focusing on adaptive responses to countermovement jump (CMJ), reactive strength index (RSI), and change of direction (COD) performance in groups of female youth divided by maturation status (years from peak height velocity [PHV]). The training program lasted 7 weeks with subjects undertaking 2 sessions of PT per week. In the mid-PHV group, there was a small increase (effect size; 90% confidence interval = 0.40; -0.23 to 1.03) in CMJ performance. No changes were observed in the post-PHV group (0.02; -0.68 to 0.72). For RSI, there was a moderate increase in the mid-PHV group (0.94; 0.29-1.59) with only a trivial increase in the post-PHV group (0.06; -0.65 to 0.76). The intervention exerted no positive effect on COD performance in any group. Plyometric training seems to enhance CMJ and RSI in female youth, although the magnitude of adaptation could be affected by maturation status. A twice-per-week program of multidirectional jumping and hopping, with bilateral and unilateral components, can be used as a preparatory precursor to physical education classes or recreational sport. KW - girls KW - exercise KW - sport KW - athlete Y1 - 2021 U6 - https://doi.org/10.1519/JSC.0000000000003216 SN - 1064-8011 SN - 1533-4287 VL - 35 IS - 10 SP - 2690 EP - 2697 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Puschmann, Anne-Katrin A1 - Lin, Chiao-I A1 - Wippert, Pia-Maria T1 - Sustainability of a motor control exercise intervention BT - Analysis of long-term effects in a low back pain study JF - Frontiers in sports and active living N2 - Development of chronic pain after a low back pain episode is associated with increased pain sensitivity, altered pain processing mechanisms and the influence of psychosocial factors. Although there is some evidence that multimodal therapy (such as behavioral or motor control therapy) may be an important therapeutic strategy, its long-term effect on pain reduction and psychosocial load is still unclear. Prospective longitudinal designs providing information about the extent of such possible long-term effects are missing. This study aims to investigate the long-term effects of a homebased uni- and multidisciplinary motor control exercise program on low back pain intensity, disability and psychosocial variables. 14 months after completion of a multicenter study comparing uni- and multidisciplinary exercise interventions, a sample of one study center (n = 154) was assessed once more. Participants filled in questionnaires regarding their low back pain symptoms (characteristic pain intensity and related disability), stress and vital exhaustion (short version of the Maastricht Vital Exhaustion Questionnaire), anxiety and depression experiences (the Hospital and Anxiety Depression Scale), and pain-related cognitions (the Fear Avoidance Beliefs Questionnaire). Repeated measures mixed ANCOVAs were calculated to determine the long-term effects of the interventions on characteristic pain intensity and disability as well as on the psychosocial variables. Fifty four percent of the sub-sample responded to the questionnaires (n = 84). Longitudinal analyses revealed a significant long-term effect of the exercise intervention on pain disability. The multidisciplinary group missed statistical significance yet showed a medium sized long-term effect. The groups did not differ in their changes of the psychosocial variables of interest. There was evidence of long-term effects of the interventions on pain-related disability, but there was no effect on the other variables of interest. This may be partially explained by participant's low comorbidities at baseline. Results are important regarding costless homebased alternatives for back pain patients and prevention tasks. Furthermore, this study closes the gap of missing long-term effect analysis in this field. KW - MiSpEx KW - low back pain KW - long-term effects KW - multidisciplinary intervention KW - sustainability Y1 - 2021 U6 - https://doi.org/10.3389/fspor.2021.659982 SN - 2624-9367 VL - 3 SP - 1 EP - 8 PB - Frontiers Media CY - Lausanne, Schweiz ER - TY - JOUR A1 - Hagoort, Iris A1 - Vuillerme, Nicolas A1 - Hortobágyi, Tibor A1 - Lamoth, Claudine J. C. T1 - Outcome-dependent effects of walking speed and age on quantitative and qualitative gait measures JF - Gait & posture N2 - Background: Walking speed predicts many clinical outcomes in old age. However, a comprehensive assessment of how walking speed affects accelerometer based quantitative and qualitative gait measures in younger and older adults is lacking. Research question: What is the relationship between walking speed and quantitative and qualitative gait outcomes in younger and older adults? Methods: Younger (n = 27, age: 21.6) and older participants (n = 27, age: 69.5) completed 340 steps on a treadmill at speeds of 0.70 to a maximum of 1.75 m.s(-1). We used generalized additive mixed models to determine the relationship between walking speed and quantitative (stride length, stride time, stride frequency and their variability) and qualitative (stride regularity, stability, smoothness, symmetry, synchronization, predictability) gait measures extracted from trunk accelerations. Results: The type of relationship between walking speed and the majority of gait measures (quantitative and qualitative) was characterized as logarithmic, with more prominent speed-effects at speeds below 1.20 m.s(-1). Changes in quantitative measures included shorter strides, longer stride times, and a lower stride frequency, with more variability at lower speeds independent of age. For qualitative measures, we found a decrease in gait symmetry, stability and regularity in all directions with decreasing speeds, a decrease in gait predictability (Vertical, V, anterior-posterior, AP) and stronger gait synchronization (AP-mediolateral, ML, AP-V), and direction dependent effects of gait smoothness, which decreased in V direction, but increased in AP and ML directions with decreasing speeds. We found outcome-dependent effects of age on the quantitative and qualitative gait measures, with either no differences between age-groups, age-related differences that existed regardless of speed, and age-related differences in the type of relationship with walking speed. Significance: The relationship between walking speed and quantitative and qualitative gait measures, and the effects of age on this relationship, depends on the type of gait measure studied. KW - Gait quality and quantity KW - Aging KW - Walking speed KW - Treadmill KW - Generalized KW - additive mixed models Y1 - 2022 U6 - https://doi.org/10.1016/j.gaitpost.2022.01.001 SN - 0966-6362 SN - 1879-2219 VL - 93 SP - 39 EP - 46 PB - Elsevier CY - Clare ER - TY - JOUR A1 - Quarmby, Andrew James A1 - Mönnig, Jamal A1 - Mugele, Hendrik A1 - Henschke, Jakob A1 - Kim, MyoungHwee A1 - Cassel, Michael A1 - Engel, Tilman T1 - Biomechanics and lower limb function are altered in athletes and runners with achilles tendinopathy compared with healthy controls: A systematic review JF - Frontiers in Sports and Active Living N2 - Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of “medial collapse”. Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn. KW - achilles tendinopathy KW - biomechanics KW - neuromuscular KW - kinetics KW - electromyography KW - athletes KW - runners KW - kinematics Y1 - 2023 U6 - https://doi.org/10.3389/fspor.2022.1012471 SN - 2624-9367 PB - Frontiers CY - Lausanne, Schweiz ER - TY - JOUR A1 - Behrens, Martin A1 - Gube, Martin A1 - Chaabene, Helmi A1 - Prieske, Olaf A1 - Zenon, Alexandre A1 - Broscheid, Kim-Charline A1 - Schega, Lutz A1 - Husmann, Florian A1 - Weippert, Matthias T1 - Fatigue and human performance BT - an updated framework JF - Sports medicine : an international journal of applied medicine and science in sport and exercise N2 - Fatigue has been defined differently in the literature depending on the field of research. The inconsistent use of the term fatigue complicated scientific communication, thereby limiting progress towards a more in-depth understanding of the phenomenon. Therefore, Enoka and Duchateau (Med Sci Sports Exerc 48:2228-38, 2016, [3]) proposed a fatigue framework that distinguishes between trait fatigue (i.e., fatigue experienced by an individual over a longer period of time) and motor or cognitive task-induced state fatigue (i.e., self-reported disabling symptom derived from the two interdependent attributes performance fatigability and perceived fatigability). Thereby, performance fatigability describes a decrease in an objective performance measure, while perceived fatigability refers to the sensations that regulate the integrity of the performer. Although this framework served as a good starting point to unravel the psychophysiology of fatigue, several important aspects were not included and the interdependence of the mechanisms driving performance fatigability and perceived fatigability were not comprehensively discussed. Therefore, the present narrative review aimed to (1) update the fatigue framework suggested by Enoka and Duchateau (Med Sci Sports Exerc 48:2228-38, 2016, [3]) pertaining the taxonomy (i.e., cognitive performance fatigue and perceived cognitive fatigue were added) and important determinants that were not considered previously (e.g., effort perception, affective valence, self-regulation), (2) discuss the mechanisms underlying performance fatigue and perceived fatigue in response to motor and cognitive tasks as well as their interdependence, and (3) provide recommendations for future research on these interactions. We propose to define motor or cognitive task-induced state fatigue as a psychophysiological condition characterized by a decrease in motor or cognitive performance (i.e., motor or cognitive performance fatigue, respectively) and/or an increased perception of fatigue (i.e., perceived motor or cognitive fatigue). These dimensions are interdependent, hinge on different determinants, and depend on body homeostasis (e.g., wakefulness, core temperature) as well as several modulating factors (e.g., age, sex, diseases, characteristics of the motor or cognitive task). Consequently, there is no single factor primarily determining performance fatigue and perceived fatigue in response to motor or cognitive tasks. Instead, the relative weight of each determinant and their interaction are modulated by several factors. Y1 - 2022 U6 - https://doi.org/10.1007/s40279-022-01748-2 SN - 0112-1642 SN - 1179-2035 VL - 53 IS - 1 SP - 7 EP - 31 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Chaabene, Helmi A1 - Negra, Yassine A1 - Moran, Jason A1 - Prieske, Olaf A1 - Sammoud, Senda A1 - Ramirez-Campillo, Rodrigo A1 - Granacher, Urs T1 - Plyometric training improves not only measures of linear speed, power, and change-of-direction speed but also repeated sprint ability in young female handball players JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - This study examined the effects of an 8-week plyometric training (PT) program on components of physical fitness in young female handball players. Twenty-one female adolescent handball players were assigned to an experimental group (EG, n = 12; age = 15.9 +/- 0.2 years) or an active control group (CG, n = 9, age = 15.9 +/- 0.3 years). While EG performed plyometric exercises in replacement of some handball-specific drills, CG maintained the regular training schedule. Baseline and follow-up tests were performed for the assessment of linear speed (i.e., 5-, 10-, and 20-m time), change-of-direction (CoD) speed (i.e., T-test time), muscle power (i.e., countermovement jump [CMJ] height and reactive strength index [RSI]), and repeated sprint ability (RSA) (RSA total time [RSA(total)], RSA best time [RSA(best)], and RSA fatigue index [RSA(FI)]). Data were analyzed using magnitude-based inferences. Within-group analyses for the EG revealed moderate-to-large improvements for the 5-m (effect size [ES] = 0.81 [0.1-1.5]), 10-m sprint time (ES = 0.84 [0.1-1.5]), RSI (ES = 0.75 [0.1-1.4]), RSA(FI) (ES = 0.65 [0.0-1.3]), and T-test time (ES = 1.46 [0.7-2.2]). Trivial-to-small ES was observed for RSA(best) (ES = 0.18 [-0.5 to 0.9]), RSA(total) (ES = 0.45 [-0.2 to 1.1]), 20-m sprint time (ES = 0.56 [-0.1 to 1.2]), and CMJ height (ES = 0.57 [-0.1 to 1.3]). For the CG, within-group analyses showed a moderate performance decline for T-test time (ES = -0.71 [-1.5 to 0.1]), small decreases for 5-m sprint time (ES = -0.46 [-1.2 to 0.3]), and a trivial decline for 10-m (ES = -0.10 [-0.9 to 0.7]) and 20-m sprint times (ES = -0.16 [-0.9 to 0.6]), RSA(total) (ES = 0.0 [-0.8 to 0.8]), and RSA(best) (ES = -0.20 [-0.9 to 0.6]). The control group achieved trivial-to-small improvements for CMJ height (ES = 0.10 [-0.68 to 0.87]) and RSI (ES = 0.30 [-0.5 to 1.1]). In conclusion, a short-term in-season PT program, in replacement of handball-specific drills, is effective in improving measures of physical fitness (i.e., linear/CoD speed, jumping, and RSA) in young female handball players. KW - stretch-shortening cycle KW - physical fitness KW - young athletes Y1 - 2021 U6 - https://doi.org/10.1519/JSC.0000000000003128 SN - 1064-8011 SN - 1533-4287 VL - 35 IS - 8 SP - 2230 EP - 2235 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Lehmann, Nico A1 - Kuhn, Yves-Alain A1 - Keller, Martin A1 - Aye, Norman A1 - Herold, Fabian A1 - Draganski, Bogdan A1 - Taube, Wolfgang A1 - Taubert, Marco T1 - Brain activation during active balancing and its behavioral relevance in younger and older adults BT - a functional near-infrared spectroscopy (fNIRS) study JF - Frontiers in Aging Neuroscience N2 - Age-related deterioration of balance control is widely regarded as an important phenomenon influencing quality of life and longevity, such that a more comprehensive understanding of the neural mechanisms underlying this process is warranted. Specifically, previous studies have reported that older adults typically show higher neural activity during balancing as compared to younger counterparts, but the implications of this finding on balance performance remain largely unclear. Using functional near-infrared spectroscopy (fNIRS), differences in the cortical control of balance between healthy younger (n = 27) and older (n = 35) adults were explored. More specifically, the association between cortical functional activity and balance performance across and within age groups was investigated. To this end, we measured hemodynamic responses (i.e., changes in oxygenated and deoxygenated hemoglobin) while participants balanced on an unstable device. As criterion variables for brain-behavior-correlations, we also assessed postural sway while standing on a free-swinging platform and while balancing on wobble boards with different levels of difficulty. We found that older compared to younger participants had higher activity in prefrontal and lower activity in postcentral regions. Subsequent robust regression analyses revealed that lower prefrontal brain activity was related to improved balance performance across age groups, indicating that higher activity of the prefrontal cortex during balancing reflects neural inefficiency. We also present evidence supporting that age serves as a moderator in the relationship between brain activity and balance, i.e., cortical hemodynamics generally appears to be a more important predictor of balance performance in the older than in the younger. Strikingly, we found that age differences in balance performance are mediated by balancing-induced activation of the superior frontal gyrus, thus suggesting that differential activation of this region reflects a mechanism involved in the aging process of the neural control of balance. Our study suggests that differences in functional brain activity between age groups are not a mere by-product of aging, but instead of direct behavioral relevance for balance performance. Potential implications of these findings in terms of early detection of fall-prone individuals and intervention strategies targeting balance and healthy aging are discussed. KW - aging KW - neuroimaging KW - functional near-infrared spectroscopy (fNIRS) KW - balance KW - postural control KW - prefrontal cortex KW - neural inefficiency Y1 - 2022 U6 - https://doi.org/10.3389/fnagi.2022.828474 SN - 1663-4365 VL - 14 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Quarmby, Andrew James A1 - Khajooei, Mina A1 - Engel, Tilman A1 - Kaplick, Hannes A1 - Mayer, Frank T1 - The feasibility of a split-belt instrumented treadmill running protocol with perturbations JF - Journal of biomechanics N2 - Unexpected perturbations during locomotion can occur during daily life or sports performance. Adequate compensation for such perturbations is crucial in maintaining effective postural control. Studies utilising instrumented treadmills have previously validated perturbed walking protocols, however responses to perturbed running protocols remain less investigated. Therefore, the purpose of this study was to investigate the feasibility of a new instrumented treadmill-perturbed running protocol.
Fifteen participants (age = 2 8 +/- 3 years; height = 172 +/- 9 cm; weight = 69 +/- 10 kg; 60% female) completed an 8-minute running protocol at baseline velocity of 2.5 m/s (9 km/h), whilst 15 one-sided belt perturbations were applied (pre-set perturbation characteristics: 150 ms delay (post-heel contact); 2.0 m/s amplitude; 100 ms duration). Perturbation characteristics and EMG responses were recorded. Bland-Altman analysis (BLA) was employed (bias +/- limits of agreement (LOA; bias +/- 1.96*SD)) and intra-individual variability of repeated perturbations was assessed via Coefficients of Variation (CV) (mean +/- SD).
On average, 9.4 +/- 2.2 of 15 intended perturbations were successful. Perturbation delay was 143 +/- 10 ms, amplitude was 1.7 +/- 0.2 m/s and duration was 69 +/- 10 ms. BLA showed -7 +/- 13 ms for delay, -0.3 +/- 0.1 m/s for amplitude and -30 +/- 10 ms for duration. CV showed variability of 19 +/- 4.5% for delay, 58 +/- 12% for amplitude and 30 +/- 7% for duration. EMG RMS amplitudes of the legs and trunk ranged from 113 +/- 25% to 332 +/- 305% when compared to unperturbed gait. This study showed that the application of sudden perturbations during running can be achieved, though with increased variability across individuals. The perturbations with the above characteristics appear to have elicited a neuromuscular response during running. KW - Lower-extremity perturbations KW - Split-belt treadmill KW - Running KW - Stumbling KW - EMC Y1 - 2020 U6 - https://doi.org/10.1016/j.jbiomech.2019.109493 SN - 0021-9290 SN - 1873-2380 VL - 98 PB - Elsevier CY - Oxford ER -