Muscles, Volume 4, Issue 2 (June 2025) – 7 articles

This study examined the impact of different breath-holding conditions on iliopsoas and other hip flexor muscle activity in individuals with chronic ankle instability (CAI). It has been hypothesised that impaired diaphragmatic function influences iliopsoas activation, potentially contributing to motor control deficits in patients with CAI. Eleven adults with a history of chronic ankle sprain participated in this study. Maximal isometric hip flexion was assessed under three breath-holding conditions: end-expiration, end-inspiration, and the intermediate state. Surface electromyography was used to record the muscle activity of the iliopsoas, rectus femoris, sartorius, and tensor fasciae latae, while the peak hip flexion torque was measured using an isokinetic dynamometer. Under the end-inspiration condition, iliopsoas activity on the affected side was significantly lower than that on the control side (p < 0.05). However, no significant differences were observed between the affected and control sides in the activity of the other hip flexor muscles or the peak hip flexion torque across breath-holding conditions. This study highlights the association between reduced iliopsoas activity during end-inspiration and compromised diaphragmatic function in patients with CAI. Future research should explore dynamic movement tasks and larger sample sizes to elucidate neuromuscular mechanisms further and refine rehabilitation strategies. Full article

This systematic review aims to evaluate the impact of hormonal fluctuations during the menstrual cycle on the performance of female athletes. Methods: Following PRISMA guidelines, a comprehensive search was conducted in Scopus, Web of Science, and PubMed databases using the keywords: (“Menstrual cycle”) AND (“performance” OR “female athlete” OR “sport” AND NOT “male”); AND NOT (“contraceptive”). Inclusion criteria focused on original studies published between 2013 and 2023, in English or Spanish, involving eumenorrheic female athletes without menstrual disorders or oral contraceptive use. The studies were critically assessed using the McMaster scientific review method. Results: Thirteen eligible articles were reviewed, comprising a total sample of 152 athletes. Significant findings include increased flexibility during the ovulatory phase and enhanced aerobic and anaerobic capacities in the luteal phase. Additionally, the menstrual and premenstrual phases notably influenced aerobic and anaerobic capacities, performance perception, symptomatology, and exercise-induced muscle damage. Conclusion: Hormonal fluctuations can impact female athletes’ performance. However, further research is warranted due to inconsistent results stemming from variations in cycle phases studied, lack of standardized methodologies, small sample sizes, and short observation periods. Full article

The strength and conditioning literature examining neuromuscular physiology, bioenergetics, neuroendocrine factors, nutrition and metabolic factors, and the use of ergogenic aids, as well as physical and physiological responses and adaptations, have clearly identified the benefits of participating in regular resistance training programs for athletic populations, especially as it relates to improving muscular strength. Beyond evidence-based research, models for resistance training program implementation are of considerable value for optimizing athletic performance. In fact, several have been provided that address general to specific characteristics of athleticism (i.e., strength endurance, muscular strength, and muscular power) through resistance training over the decades. For instance, a published model known as the strength–endurance continuum that enhances dynamic correspondence (i.e., training specificity) in athletic populations by developing structural, metabolic, and neural capacities across a high-load, low-repetition and low-load, high-repetition range. Further models have been developed to enhance performance approaches (i.e., optimum performance training model) and outcomes (i.e., performance pyramid), even within specific populations, such as youth (i.e., youth physical development model). The ten, five, three, or 10-5-3 (TFT) model for strength and conditioning professionals synthesizes currently available information and provides a framework for the effective implementation of resistance training approaches to suit the needs of athletes at each stage of development. The model includes three key components to consider when designing strength and conditioning programs, denoted by the acronym TFT (ten, five, three). Over recent years, the model has gained much support from teams, coaches, and athletes, mainly due to the ability to streamline common knowledge within the field into an efficient and effective resistance training system. Furthermore, this model is distinctly unique from others as it prioritizes the development of strength–endurance, muscular strength, and muscular power concurrently. This paper explains the model itself and begins to provide recommendations for those interested in implementing TFT-based approaches, including a summary of points as a brief take-home guide to implementing TFT interventions. It is the author’s hope that this paper encourages other performance professionals to share their models to appreciate human ingenuity and advance our understanding of individualized approaches and systems towards the physical development of the modern-day athlete. Full article

Benign paroxysmal torticollis (BPT) is a condition characterized by episodes of alternating head tilt in infants. Mild cases may be mistaken for Congenital Muscular Torticollis, potentially leading to unnecessary treatment. This case report describes an infant with suspected mild BPT who exhibited alternating head tilt and colic but demonstrated normal motor development. The head tilt resolved spontaneously without intervention. Physical therapists should be aware of mild benign paroxysmal torticollis and monitor such cases carefully to differentiate it from other forms of torticollis and to provide reassurance to parents. Full article

Hip injuries are common in contact sports, particularly in high-impact activities. A well-known type of hip trauma is the hip pointer, which is a contusion of the iliac crest caused by a direct blow. Typically, hip pointers involve the lateral aspect of the iliac crest. In this case report, we present an unusual variation of this injury affecting the posterior iliac crest near the posterior superior iliac spine (PSIS). We describe two cases of elite athletes who sustained posterior iliac crest trauma, a condition we propose naming the “posterior hip pointer”. This report highlights the clinical presentation, imaging findings, treatment approach, and implications for sports medicine. Full article

Improving and maintaining an ideal body composition is important for sporting achievement and good health. Body composition assessment is therefore a tool used to monitor training and to evaluate the objectives of a training plan for health purposes. Ultrasound (US) emerges as an alternative to evaluate the thickness of subcutaneous cellular tissue, as well as muscle thickness: (1) Background: We aim to evaluate and compare the anthropometric and ultrasound measurements used to quantify the effects of strength training. (2) Methods: A total of 31 students (22.3 ± 4.14 years of age), 25 men and 6 women, from the Professional Programme in Sport were enrolled in the Physical Preparation course at the Institución Universitaria Politécnico Colombiano Jaime Isaza Cadavid. Protocol: Pre- and post-intervention ultrasound and anthropometric evaluations of a strength training programme with a predominance of the eccentric component were performed three times a week for 4 weeks. For the pre- and post-intervention relationship of the quantitative anthropometric and ultrasound variables, the Wilcoxon signed-rank test was used; the effect size of a Wilcoxon test was also calculated using the rank correlation, and the correlation of the anthropometric and ultrasound variables was determined using Spearman’s correlation coefficient, with a p-value < 0.05 considered statistically significant. (3) Results: There were no statistically significant differences in the anthropometric variables assessed, but there were significant differences in measures of quadricep muscle size and in the control parameter echo-intensity (EI) of subcutaneous fat in the variables. (4) Conclusions: The US of the quadriceps can measure changes in muscle thickness even without changes in muscle mass assessed by anthropometry, making it an excellent tool for the evaluation and monitoring of strength training. Full article

Non-contact injuries are common in collegiate throwing athletes. Identifying musculoskeletal issues that predispose athletes to injuries would be valuable for reducing the associated risk. The purpose of this pilot study was to use binomial logistic regression to identify injury-prone athletes with multiple pre-season functional measures and demographic information. Eighteen Division II baseball and softball athletes underwent pre-season functional testing including measures of manual muscle testing of the dominant shoulder muscles (MMT), the functional movement screen (FMS), and closed kinetic chain upper extremity stability (CKCUES). A certified athletic trainer at the university diagnosed and documented the injuries that these athletes sustained over the course of the season. Binomial logistic regression models were used to assess the effects of FMS composite score, CKCUES normative score, MMT scores, and demographic information on the likelihood that participants would sustain (a) any type of injury and (b) a shoulder injury during the competitive season. The model for injury was not significant (p = 0.822), correctly classifying 72.2% of cases. The model for shoulder injury was significant (p = 0.039) and correctly classified 100% of cases. These results suggest that shoulder injury incidence may potentially be predicted using sport-specific movement tests in baseball and softball athletes. A larger sample size is needed to verify these results in the future. Full article