Mineral Density and Markers of Bone Remodelling in Young Athletes in Response to Weightlifting Exercise: A Pilot Study

Background: Weightlifting is a practice that exerts a high degree of pressure on the skeleton when supporting large loads of weight. The practice of exercise contributes by improving bone mineral density (BMD) and can prevent problems associated with low BMD. Objective: The objective of the present study was to determine BMD and measure bone turnover using blood markers in weightlifting athletes in response to exercise. Methods: The study included 16 athletes and 16 controls of both sexes in the range of 18 to 22 years old. BMD was determined at the femoral neck, hip, lumbar spine, and Total Mineral Density (TMD). The value of the total mineral density (TMDV) was obtained from the sum of the BMD of the evaluated regions. Bone formation and resorption in blood were evaluated by Alkaline Phosphatase (ALP) and Acid Phosphatase (ACP), respectively. In addition, the concentration of urea and Creatine Kinase (CK) were determined. Results: The mean BMD of the lumbar spine and TMDV was of 1.2 g/cm2 in female and male athletes. In young people who did not practice weightlifting, BMD in the lumbar spine (0.9 g/cm2 in both groups) and TMDV (1.05 g/cm2 in women and 1.11 g/cm2 in men) were significantly lower (p <0.05). The activity in bone formation and CK in male athletes was twice as high compared to the other groups. The blood urea concentration in athletes (32.7- 38.0 mg/dL) was significantly higher (p <0.05) compared to the control groups (19.3-18.8 mg/dL). Conclusion: The practice of weightlifting benefits bone mass gain in the lumbar spine. These findings suggest that exercises in which high weight loads are supported promote bone turnover and mineralization to prevent bone weakening.

Exercise in virtual reality with a muscular avatar influences performance on a weightlifting exercise

Virtual Reality (VR) technology can be used to influence performance on endurance exercises. In this study, we focused on manipulating perception of own-body strength by exercising in VR as a muscular avatar. In this repeated-measure study, twenty-nine participants performed biceps curl exercise in a maximum repetitions protocol, up to exhaustion. The exercise was done either in VR as a muscular avatar, or without VR, in front of the mirror. Dependent variables were the number of exercise repetitions and self-reported exertion. We also controlled blood glucose level, perceived weight of the barbell and level of embodiment. Participants performed significantly more biceps curl repetitions in the VR condition (Z = -2.05, p < .05) with an effect size of d = 0.36. The self-reported effort did not differ significantly between conditions. The results of this study may have an applied significance since number of exercise repetitions is an ecologically valid measure, directly relevant to real training protocols.

Effects of Dietary Nitrate Supplementation on Weightlifting Exercise Performance in Healthy Adults: A Systematic Review

Dietary nitrate (NO3−) supplementation has been evidenced to induce an ergogenic effect in endurance and sprint-type exercise, which may be underpinned by enhanced muscle contractility and perfusion, particularly in type II muscle fibers. However, limited data are available to evaluate the ergogenic potential of NO3− supplementation during other exercise modalities that mandate type II fiber recruitment, such as weightlifting exercise (i.e., resistance exercise). In this systematic review, we examine the existing evidence basis for NO3− supplementation to improve muscular power, velocity of contraction, and muscular endurance during weightlifting exercise in healthy adults. We also discuss the potential mechanistic bases for any positive effects of NO3− supplementation on resistance exercise performance. Dialnet, Directory of Open Access Journals, Medline, Pubmed, Scielo, Scopus and SPORT Discus databases were searched for articles using the keywords: nitrate or beetroot and supplement or nut*r or diet and strength or “resistance exercise” or “resistance training” or “muscular power”. Four articles fulfilling the inclusion criteria were identified. Two of the four studies indicated that NO3− supplementation could increase aspects of upper body weightlifting exercise (i.e., bench press) performance (increases in mean power/velocity of contraction/number of repetitions to failure), whereas another study observed an increase in the number of repetitions to failure during lower limb weightlifting exercise (i.e., back squat). Although these preliminary observations are encouraging, further research is required for the ergogenic potential of NO3− supplementation on weightlifting exercise performance to be determined.

Design of a Variable Stiffness Pneumatic Ankle Prosthesis With Self-Recharging for Weightlifting Exercise

With advances in prosthetic technology, functional intent has extended past basic support toward providing increased dynamic ability for daily and athletic use. Addressing a disparity between universality and complexity in sport-grade and energy-storage-and-return (ESR) prostheses, this paper presents a pneumatic transtibial ankle prosthesis concept with semi-active control of ankle stiffness to adjust the prosthesis' properties for a wider range of gym exercises. Functional validation of the device falls under specific scenarios including the parallel back squat weightlifting exercise. The prosthesis features 30 deg sagittal ankle range of motion and provides wireless adjustment of static air pressure via a smartphone app to transition between the force and stiffness demands of walking and weightlifting. This pneumatic system includes a self-replenishing feature, providing a practical solution for the variable air pressure demands of athletics and everyday use. The mechanical, pneumatic, and control systems of the prosthesis are therefore described. Biomechanical tests including the back squat were conducted with one transtibial amputee subject. The resultant kinematic analysis validated the functional goals of the device, including an increased range of ankle rotation and variable stiffness across three different cylinder pressure settings. The kinetic profiles of the amputated leg and the natural leg also reveal an improvement in bilateral symmetry compared to a standard ESR prosthesis. This prosthesis concept has the potential to help persons with amputation participate in a wider range of activities, by improving the versatility of current ESR and sport prostheses.