A comparison of bilateral muscular imbalance ratio calculations using functional tests.

Bilateral muscular imbalance can increase the risk of injury and negatively impact sporting performance. Bilateral muscular imbalances are typically calculated as ((side 1-side 2)/reference value) x 100, to provide a percentage value of the difference between limbs. Using different numerator (right-left or strong-weak) or reference values (left, right, strong, weak, average of the two) could mask or inflate the true difference value. The present study aimed to compare the bilateral muscular imbalance ratio calculations, using the absolute difference between limbs as the numerator and the five different options as reference values. Twenty three males (21.6±1.9 years, 1.80±0.06 m, 80.5±13.8 kg) and eleven females (20.8± 1.5 years, 1.62±0.03 m, 68.0±6.5 kg) performed the one-legged 6m timed test and the onelegged triple hop distance test. The five possible combinations were compared with a 2 (gender) x 2 (functional test) x 5 (calculation method) ANOVA for each test. Significant differences (P<0.05) were found between gender when the right leg was used as the reference value (males:6.1%, females:9.1%), and within calculation methods for males (range:5.9%-6.5%) and females (range:8.4%-9.4%), with low effect sizes (range: 0.07-0.26). The present findings demonstrate that using a different reference value for calculating bilateral muscular imbalances does not result in a practically significant difference. These findings can be used to inform a more standardised calculation method which will afford conditioning coaches a more correct evaluation and monitoring of training and rehabilitation programmes

Upper limb muscle strength and knee frontal plane projection angle asymmetries in female water-polo players

Water-polo players frequently perform overhead throws that could result in shoulder imbalances. For overhead throws, execution of the ‘eggbeater kick’ (cyclical movement of the legs) is required to lift the body out of the water. Although a symmetrical action, inter-limb differences in task execution could lead to knee frontal plane projec-tion (FPPA) differences. The present study examined imbalances shoulder and knee FPPA in female players. Eighteen competitive female field players (24.1 ± 5.5 years, 1.68 ± 0.06 m, 72.9 ± 13.3 kg) had their shoulder strength assessed in a shot-mimicking position with a portable dynamometer, standing and seated (isolating the shoulder contribution). Anterior: posterior and shooting: non- shooting shoulder comparison were made. Additionally, players per-formed a drop jump. Knee FPPA was recorded from digitising and comparing the frames just before landing and at stance phase. During standing, players exhibited higher shooting: non-shooting asymmetry (p = 0.032) in the anterior contraction direction, while during seated the shooting shoulder anterior: posterior asymmetry was higher (p = 0.032). Interlimb knee FPPA asymmetry was higher in the stance phase (p = 0.02). Despite the overhead throwing and egg- beater demands impacting differently on each limb, considerable asymmetries do not develop, suggesting the overall training require-ments (e.g. swimming, resistance training) were sufficient to maintain the asymmetry within desirable limits

What is the effect of ankle disk training and taping on proprioception deficit after lateral ankle sprains among active populations? - A systematic review.

To investigate the effect of disk training and tape application on diminished proprioception after Lateral Ankle Sprain (LAS) in active populations. Only clinical trials investigating the effectiveness of disk training and ankle tape on proprioception deficits following LAS by assessing JPS or kinaesthesia were included. Electronic databases of PubMed, MEDLINE, SPORTDiscus, CINAHL, Web of Science, Cochrane and PEDro were searched. The main search was conducted in February 2022. The physiotherapy Evidence Database (PEDro) scale was utilised to assess the methodological quality of each article. The search yielded six studies investigating the effects of disk training and four studies investigating the effects of inelastic tape. Five articles showed a significant improvement on JPS after disk training. However, no difference across different intervention groups was observed in one study. Only one trial presented an immediate significant improvement when taped, while another study showed that external ankle supports significantly improved JPS after 2 weeks and after 2 months. Three of four studies found no immediate improvement on proprioceptive deficits by the use of tape. This review found that disk training may improve impaired proprioception after LAS, whilst the efficacy of inelastic tape was not evident due to methodological quality of the few available studies. Further studies are needed to establish whether these interventions can be used clinically with sufficient evidence. [Abstract copyright: Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.

Exercise as a countermeasure to human ageing

In less than 200 years, life expectancy in the United Kingdom has doubled from ~40 to ~80 years, a trend mirrored in most developed and now developing countries. The healthogenic effects of staying active across the lifespan are widely promoted, yet only 36% of men and 18% of women >75 years of age in England achieve the physical activity guidelines of 150 min/wk. Reduced functional ability as we age is caused by a natural weakening of physiological systems, exacerbated by physical inactivity. This talk will discuss benefits of, and barriers to, physical activity and exercise in older cohorts, with a focus on resistance training

Bodyweight squats can induce post-activation performance enhancement on jumping performance:a brief report

Post-activation potentiation enhancement (PAPE) refers to increased force generation following a muscular conditioning pre-activity that acutely enhances subsequent strength and power performance. Athlete apprehension to use heavy weights (i.e. >80%1RM) immediately before a competition or inability to use weights before the performance (e.g. due to regulations) prevent materialising the benefits of PAPE. Therefore, this study examined whether PAPE can be induced with bodyweight squats. Sixteen healthy, team sports players (male: 10, female: 6, mean ± SD: age 22.2 ± 3.0 years, height 1.67 ± 0.08 m, body mass 70.2 ± 8.2 kg) performed three sets of ten repetitions of bodyweight squats with 30 seconds recovery between each set. A countermovement jump was performed 5 minutes before, 2 and 4 minutes after the squat sets and jump height was calculated. The results showed existence of PAPE with the jump height increasing at both 2 (30.8 ± 5.6 cm, p = 0.045, g = 0.21) and 4 (30.8 ± 6.1 cm, p = 0.037, g = 0.20) minutes, compared to baseline (29.5 ± 6.4 cm). This is the first study to use bodyweight squats rather than loaded squats. Our findings indicate that three sets of ten repetitions of squats using bodyweight only can be a sufficient stimulus to induce PAPE

Norm attaining vectors and Hilbert points

Let $H$ be a Hilbert space that can be embedded as a dense subspace of a Banach space $X$ such that the norm of the embedding is equal to $1$. We consider the following statements for a nonzero vector $\varphi$ in $H$: (A) $\|\varphi\|_X = \|\varphi\|_H$. (H) $\|\varphi+f\|_X \geq \|\varphi\|_X$ for every $f$ in $H$ such that $\langle f, \varphi \rangle =0$. We use duality arguments to establish that (A) $\implies$ (H), before turning our attention to the special case when the Hilbert space in question is the Hardy space $H^2(\mathbb{T}^d)$ and the Banach space is either the Hardy space $H^1(\mathbb{T}^d)$ or the weak product space $H^2(\mathbb{T}^d) \odot H^2(\mathbb{T}^d)$. If $d=1$, then the two Banach spaces are equal and it is known that (H) $\implies$ (A). If $d\geq2$, then the Banach spaces do not coincide and a case study of the polynomials $\varphi_\alpha(z) = z_1^2 + \alpha z_1 z_2 + z_2^2$ for $\alpha\geq0$ illustrates that the statements (A) and (H) for the two Banach spaces describe four distinct sets of functions

PREVIOUS BALLISTIC AND HEAVY CONDITIONING STIMULI CAN ACUTELY ENHANCE THROWING PERFORMANCE

The purpose of this study was to compare the effects of a ballistic and a heavy load conditioning stimulus on subsequent bench throw performance. Eleven male, competitive rugby players (mean ± SD: body mass 91.5 ± 9.6kg, height 1.79 ± 0.03 m) with at least two years of resistance training exercise performed two ballistic bench throws after warm up. Following a 10-min rest, they performed either a ballistic bench throw (BAL) or a heavy load bench press (HEAVY) conditioning stimulus. Subsequent to a 4-minute rest, they performed another two ballistic bench press throws. No significant differences were revealed for peak power, peak force, rate of force development and force at peak power for either conditioning stimulus. However, significant differences were revealed for bar displacement for the BAL group, and for peak velocity and velocity at peak power for both groups. The results suggest that a ballistic conditioning stimulus can induce post activation performance enhancement and it appears more sport specific in its results than a heavy load conditioning stimulu

To do or not to do (exercise) : physical activity in the lives of people with cerebral palsy

We examined the lives of adults with cerebral palsy who had minimal involvement in physical activity (Judy, aged 60; Alana, aged 29), who were involved in physical activity (Amy, aged 25; Ben, aged, 30), or who had minimal involvement in physical activity and who then participated in physical activity (David, aged 27; Tim, aged, 24). After receiving ethical approval, a life-history research approach (Denzin, 1989: Interpretive biography. Newbury Park, CA: Sage) was used, with the participants&rsquo; stories being interpreted using primarily psychodynamic theory (Freud, Erikson, Adler, Basch) to gain insight into their meaning and experiences of physical activity. Judy and Alana had similar childhood experiences, which included: performing difficult, and sometimes painful, physiotherapy; wearing callipers to assist their walking; lacking competence at physical activity; and being socially isolated from their classmates. These aspects of their life histories seemed to contribute to their subsequent avoidance of physical activity and early onset of functional decline.Amy and Ben had negative experiences with physical activity as children (similar to Judy and Alana), but were involved in, and valued, physical activity as adults. Physical activity was a means of displaying competence, delaying further functional loss, and becoming socially connected.David and Tim lost the ability to walk in early adolescence. The minimal physical activity in which they engaged during their adult lives was directed towards trying to walk again. Walking seemed to be intimately connected with psychosocial growth. David&rsquo;s weight-training programme seemed to provide him with another avenue for self-improvement towards his goal of attracting a life partner. Tim&rsquo;s warm-water aerobic programme provided him with an opportunity to develop competence at swimming and at walking, and to enhance his self-esteem for these activities.Involvement in physical activity may be important for people with cerebral palsy in their endeavours to successfully face the various psychosocial challenges throughout life. Implications of this research include: parents and teachers of children with cerebral palsy should provide support for their involvement in physical activity; physiotherapists should try to reduce the pain and increase the perceived relevancy of the treatments they deliver to young people with cerebral palsy; and psychologists should be aware of some of the difficulties people with cerebral palsy face and how they may manifest in adults with the condition.<br /

Interplay between body stabilisation and quadriceps muscle activation capacity.

The study aimed to distinguish the effect of stabilisation and muscle activation on quadriceps maximal isometric voluntary contraction (MVC) torque generation. Nine subjects performed (a) an MVC with restrained leg and pelvis (Typical MVC), (b) a Typical MVC with handgrip (Handgrip MVC), (c) an MVC focusing on contracting the knee extensors only (Isolated knee extension MVC), and (d) an MVC with unrestrained leg and pelvis (Unrestrained MVC). Torque and activation capacity between conditions were compared with repeated measures ANOVA and dependent t-tests. EMG (from eleven remote muscles) was compared using Friedman's and Wilcoxon. Typical MVC (277.2±49.6Nm) and Handgrip MVC (261.0±55.4Nm) were higher than Isolated knee extension MVC (210.2±48.3Nm, p<0.05) and Unrestrained MVC (195.2±49.7Nm, p<0.05) torque. Typical MVC (83.1±15.9%) activation was higher than Isolated knee extension MVC (68.9±24.3%, p<0.05), and both Typical MVC and Handgrip MVC (81.8±17.4%) were higher than Unrestrained MVC (64.9±16.2%, p<0.05). Only flexor carpi radialis, biceps brachii, triceps brachii and external oblique muscles showed EMG differences, with Isolated knee extension MVC consistently lower than Typical MVC or Handgrip MVC. Stabilisation of the involved segments is the prime concern allowing fuller activation of the muscle, reinforcing the need for close attention to stabilisation during dynamometry-based knee joint functional assessment

Previous high-intensity activity affects lower limb strength ratios

Lower limb strength ratios are important in assessing muscular imbalances. Typically, these ratios are derived from assessment of explosive, maximum effort activities. Such assessment can be functional or isokinetic. The single-effort nature of these assessments does not provide information on imbalance changes after muscular contractions. Any such change could indicate an increased risk of injury after a period of activity, thus raising questions as to the correct procedure of muscle imbalance assessment. Therefore, the aim of the current study was to assess muscle imbalances over maximum effort repeated cycling sprints. Seventeen healthy, physically active young adults (females: n=4, height 1.62±0.03 m, body mass 68.0±6.5 kg; males: n=13, height 1.80±0.06 m, body mass 80.5±13.8 kg) performed five 6-s sprints with 24-s rest interval on a Lode Excalibur bike with torque and power data recorded for each leg. Average, average maximum (average of maximum from each sprint) and peak torque (TAv, TAvM and TP respectively) and power (PAv, PAvM and PP respectively) were obtained for each leg. Ratios of these variables were calculated as . Wilcoxon's test revealed a significantly stronger leg (p<0.05) for all torque and power variables. Friedman's test indicated a significant ratio increase between TAv (11.7±6.8%) and TAvM (4.6±3.0%, p=0.001) and TP (4.1±3.5%, p=0.001), as well as between PAv (8.8±5.0%) and PAvM (4.5±2.9%, p=0.003) and PP (4.2±2.6, p=0.003%) but not between TAvM and TP (p=0.421) or PAvM and PP (p=0.981). The results indicate that high-intensity activity increases lower limb strength imbalance, resulting in different ratios. The authors posit that muscle imbalance assessment activities conducted at rested state may not accurately reflect the true strength difference between limbs, leading to inaccurate training or rehabilitation advice