Effects of the Barbell Load on the Acceleration Phase during the Snatch in Elite Olympic Weightlifting

The load-depended loss of vertical barbell velocity at the end of the acceleration phase limits the maximum weight that can be lifted. Thus, the purpose of this study was to analyze how increased barbell loads affect the vertical barbell velocity in the sub-phases of the acceleration phase during the snatch. It was hypothesized that the load-dependent velocity loss at the end of the acceleration phase is primarily associated with a velocity loss during the 1st pull. For this purpose, 14 male elite weightlifters lifted seven load-stages from 70–100% of their personal best in the snatch. The load–velocity relationship was calculated using linear regression analysis to determine the velocity loss at 1st pull, transition, and 2nd pull. A group mean data contrast analysis revealed the highest load-dependent velocity loss for the 1st pull (t = 1.85, p = 0.044, g = 0.49 [−0.05, 1.04]) which confirmed our study hypothesis. In contrast to the group mean data, the individual athlete showed a unique response to increased loads during the acceleration sub-phases of the snatch. With the proposed method, individualized training recommendations on exercise selection and loading schemes can be derived to specifically improve the sub-phases of the snatch acceleration phase. Furthermore, the results highlight the importance of single-subject assessment when working with elite athletes in Olympic weightlifting

Force production capacity and functional reflex activity in young and elderly men

Background and aims: There is growing evidence that biological aging results in impaired force production of the lower extremities and deficits in reflex activity. This study therefore investigated maximal and explosive force production capacity, functional reflex activity (FRA) during gait perturbations, and the relationship between variables of force production capacity and FRA in young and elderly men. Methods: Twenty-eight young (age 27±3 yrs, n=14) and old (age 67±4 yrs, n=14) healthy active men were tested for decelerating impulses on a treadmill and for their maximal isometric leg extension force (MIF) and rate of force development (RFD) on a leg-press. Results: MIF and RFD were significantly lower in the elderly than in younger participants (MIF ≈45%, p<0.01; RFD ≈50%, p<0.01). Elderly subjects showed significant decreases in FRA in the prime mover which compensated for the decelerating impulse (FRA ≈29%, p<0.05). No significant correlations were found between FRA, MIF or RFD. Conclusions: Lower MIF, RFD and impaired FRA were found in old compared with young men. The absence of significant correlations between measures of strength performance and FRA may indicate that different mechanisms within the neuromuscular system are responsible for these capacities. This result may imply that force production and functional reflex activity are independent of each other and may have to be trained complementaril

A Qualitative Review of Balance and Strength Performance in Healthy Older Adults: Impact for Testing and Training

A continuously greying society is confronted with specific age-related health problems (e.g., increased fall incidence/injury rate) that threaten both the quality of life of fall-prone individuals as well as the long-term sustainability of the public health care system due to high treatment costs of fall-related injuries (e.g., femoral neck fracture). Thus, intense research efforts are needed from interdisciplinary fields (e.g., geriatrics, neurology, and exercise science) to (a) elucidate neuromuscular fall-risk factors, (b) develop and apply adequate fall-risk assessment tools that can be administered in clinical practice, and (c) develop and design effective intervention programs that have the potential to counteract a large number of fall-risk factors by ultimately reducing the number of falls in the healthy elderly. This paper makes an effort to present the above-raised research topics in order to provide clinicians, therapists, and practitioners with the current state-of-the-art information

Assessment of validity and response bias in neuropsychiatric evaluations

BACKGROUND: Forensic neuropsychiatric assessment requires thorough consideration of malingering and response bias. Neuropsychiatric evaluations are complicated due to the multiple domains in which symptoms and impairment present. Moreover, symptom exaggeration in these evaluations can also present along various symptom domains (e.g., psychological, neurocognitive,somatic). Consequently, steps must be taken to ensure adequate coverage of response bias across all three domains of function. PURPOSE: The following article reviews the conceptualization of malingering in neuropsychiatric settings, as well as various approaches and measures that can be helpful in the assessment of malingering and response bias. CONCLUSIONS: Forensic neuropsychiatric assessment requires thorough consideration of malingering and response bias. These evaluations are complicated due to the multiple domains in which symptoms and impairment present. Performance and symptom validity measures should be routinely included in these evaluations. Collaboration between psychiatry and psychology can provide the optimal multi-method approach needed for thorough neuropsychiatric assessment in forensic cases. We illustrate our points with two case studies from forensic traumatic brain injury neuropsychiatric evaluations

Associations between measures of physical fitness and cognitive performance in preschool children

BACKGROUND Given that recent studies report negative secular declines in physical fitness, associations between fitness and cognition in childhood are strongly discussed. The preschool age is characterized by high neuroplasticity which effects motor skill learning, physical fitness, and cognitive development. The aim of this study was to assess the relation of physical fitness and attention (including its individual dimensions (quantitative, qualitative)) as one domain of cognitive performance in preschool children. We hypothesized that fitness components which need precise coordination compared to simple fitness components are stronger related to attention. METHODS Physical fitness components like static balance (i.e., single-leg stance), muscle strength (i.e., handgrip strength), muscle power (i.e., standing long jump), and coordination (i.e., hopping on one leg) were assessed in 61 healthy children (mean age 4.5 ± 0.6 years; girls n = 30). Attention was measured with the "Konzentrations-Handlungsverfahren für Vorschulkinder" [concentration-action procedure for preschoolers]). Analyses were adjusted for age, body height, and body mass. RESULTS Results from single linear regression analysis revealed a significant (p < 0.05) association between physical fitness (composite score) and attention (composite score) (standardized ß = 0.40), showing a small to medium effect (F$^{2}$ = 0.14). Further, coordination had a significant relation with the composite score and the quantitative dimension of attention (standardized ß = 0.35; p < 0.01; standardized ß =  - 0.33; p < 0.05). Coordination explained about 11% (composite score) and 9% (quantitative dimension) of the variance in the stepwise multiple regression model. CONCLUSION The results indicate that performance in physical fitness, particularly coordination, is related to attention in preschool children. Thus, high performance in complex fitness components (i.e., hopping on one leg) tends to predict attention in preschool children. Further longitudinal studies should focus on the effectiveness of physical activity programs implementing coordination and complex exercises at preschool age to examine cause-effect relationships between physical fitness and attention precisely

Effects of Isokinetic Training on Trunk Muscle Fitness and Body Composition in World-Class Canoe Sprinters

In canoe sprint, the trunk muscles play an important role in stabilizing the body in an unstable environment (boat) and in generating forces that are transmitted through the shoulders and arms to the paddle for propulsion of the boat. Isokinetic training is well suited for sports in which propulsion is generated through water resistance due to similarities in the resistive mode. Thus, the purpose of this study was to determine the effects of isokinetic training in addition to regular sport-specific training on trunk muscular fitness and body composition in world-class canoeists and to evaluate associations between trunk muscular fitness and canoe-specific performance. Nine world-class canoeists (age: 25.6 ± 3.3 years; three females; four world champions; three Olympic gold medalists) participated in an 8-week progressive isokinetic training with a 6-week block “muscle hypertrophy” and a 2-week block “muscle power.” Pre- and post-tests included the assessment of peak isokinetic torque at different velocities in concentric (30 and 140∘s-1) and eccentric (30 and 90∘s-1) mode, trunk muscle endurance, and body composition (e.g., body fat, segmental lean mass). Additionally, peak paddle force was assessed in the flume at a water current of 3.4 m/s. Significant pre-to-post increases were found for peak torque of the trunk rotators at 30∘s-1 (p = 0.047; d = 0.4) and 140∘s-1 (p = 0.014; d = 0.7) in concentric mode. No significant pre-to-post changes were detected for eccentric trunk rotator torque, trunk muscle endurance, and body composition (p > 0.148). Significant medium-to-large correlations were observed between concentric trunk rotator torque but not trunk muscle endurance and peak paddle force, irrespective of the isokinetic movement velocity (all r ≥ 0.886; p ≤ 0.008). Isokinetic trunk rotator training is effective in improving concentric trunk rotator strength in world-class canoe sprinters. It is recommended to progressively increase angular velocity from 30∘s-1 to 140∘s-1 over the course of the training period

Association Between Foundation Strength and Weightlifting Exercises in Highly Trained Weightlifters:Support for a General Strength Component

Zecchin, A, Puggina, EF, Hortobágyi, T, and Granacher, U. Association between foundation strength and weightlifting exercises in highly trained weightlifters: support for a general strength component. J Strength Cond Res XX(X): 000-000, 2022-In addition to specific weightlifting exercises (i.e., clean and jerk and snatch), foundation strength exercises (i.e., overhead press, front squat, and deadlift) constitute an integral part of the weightlifters' training regime. The unexamined concept behind this training plan is that foundation strength exercises are associated with clean and jerk and snatch performance, implying the existence of a general strength component. We thus determined the relationship between performance in foundation strength exercises (overhead press, front squat, and deadlift) and weightlifting exercises (clean and jerk and snatch) in weightlifters. Well-trained weightlifters (N = 19, age: 26.8 ± 4.4 years; body mass index: 27.6 ± 2.3 kg·m-2; and training history: 4.6 ± 0.8 years) performed 1 repetition maximum tests (1RM) in foundation strength and weightlifting exercises, over 14 days, in a randomized order. We observed significant correlations in 1RM performance between the overhead press and snatch (r = 0.69), front squat and snatch (r = 0.73), overhead press and clean and jerk (r = 0.67), and front squat and clean and jerk (r = 0.72, all r values: p &lt; 0.01). No significant correlations were found for 1RM performance between the snatch and deadlift or between the clean and jerk and deadlift (r-range: 0.20-0.58; p &gt; 0.05). Stepwise linear regression revealed that 1RM performance in the overhead press and front squat explained 62% of the variance in snatch 1RM performance (F = 5.51; p &lt; 0.04). Overhead press and front squat 1RM performance explained 59% of the variance in the clean and jerk 1RM performance (F = 5.14; p &lt; 0.04). Our results demonstrate the existence of a general strength component between selected foundation strength exercises and weightlifting performance. However, the use of the front squat and overhead press to increase 1RM performance in weightlifting exercises needs to be determined in future research using a different methodological approach (i.e., longitudinal protocols), given that the observed correlations do not necessarily imply causation.</p

Small and inconsistent effects of whole body vibration on athletic performance:a systematic review and meta-analysis

We quantified the acute and chronic effects of whole body vibration on athletic performance or its proxy measures in competitive and/or elite athletes. Systematic literature review and meta-analysis. Whole body vibration combined with exercise had an overall 0.3 % acute effect on maximal voluntary leg force (-6.4 %, effect size = -0.43, 1 study), leg power (4.7 %, weighted mean effect size = 0.30, 6 studies), flexibility (4.6 %, effect size = -0.12 to 0.22, 2 studies), and athletic performance (-1.9 %, weighted mean effect size = 0.26, 6 studies) in 191 (103 male, 88 female) athletes representing eight sports (overall effect size = 0.28). Whole body vibration combined with exercise had an overall 10.2 % chronic effect on maximal voluntary leg force (14.6 %, weighted mean effect size = 0.44, 5 studies), leg power (10.7 %, weighted mean effect size = 0.42, 9 studies), flexibility (16.5 %, effect size = 0.57 to 0.61, 2 studies), and athletic performance (-1.2 %, weighted mean effect size = 0.45, 5 studies) in 437 (169 male, 268 female) athletes (overall effect size = 0.44). Whole body vibration has small and inconsistent acute and chronic effects on athletic performance in competitive and/or elite athletes. These findings lead to the hypothesis that neuromuscular adaptive processes following whole body vibration are not specific enough to enhance athletic performance. Thus, other types of exercise programs (e.g., resistance training) are recommended if the goal is to improve athletic performance