Sandra Hunter

Sandra Hunter
Marquette University · Department of Physical Therapy

PhD

About

284
Publications
35,757
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
10,162
Citations
Introduction
Skills and Expertise

Publications

Publications (284)
Article
Sex differences in sports performances continue to attract considerable scientific and public attention, driven in part by high profile cases of: 1) biological male (XY) athletes who seek to compete in the female category after gender transition, and 2) XY athletes with medical syndromes collectively known as disorders or differences of sex develop...
Article
Full-text available
The cellular causes of the age‐related loss in power output and increased fatigability are unresolved. We previously observed that the depressive effects of hydrogen (H⁺) (pH 6.2) and inorganic phosphate (Pi) (30 mm) did not differ in muscle fibres from young and older men. However, the effects may have been saturated in the severe fatigue‐mimickin...
Conference Paper
Fatigability of limb muscles during high-intensity dynamic exercise is postulated to be determined by the accumulation of metabolites, namely hydrogen ions (H+) and inorganic phosphate (Pi). We previously showed that the increased fatigability of older adults during dynamic exercise was accompanied by a greater accumulation of metabolites compared...
Article
The mechanisms for the loss in limb muscle power output in old (60-79years) and very old (≥80years) adults and whether the mechanisms differ between men and women are not well-understood. We compared maximal peak power of the knee extensor muscles between young, old, and very old men and women and identified the neural and muscular factors contribu...
Article
Full-text available
Sex as a biological variable is an underappreciated aspect of biomedical research, with its importance emerging in more recent years. This review assesses the current understanding of sex differences in human physical performance. Males outperform females in many physical capacities because they are faster, stronger and more powerful, particularly...
Article
Full-text available
Sports participation confers many health benefits yet greatly increases injury risk. Long-term health outcomes in former athletes and transition to life after competitive sports are understudied. Ending a sport may pose physical and psychosocial challenges. The purpose was to determine the lived experiences of former competitive athletes and how th...
Article
INTRODUCTION: In addition to baseline muscle weakness, stroke survivors often demonstrate increased neuromuscular fatigability (an acute exercise-induced reduction in power, hereafter referred to as fatigability), which limits endurance during functional tasks. Ischemic conditioning (IC) is a non-invasive and easy-to-administer intervention that ca...
Article
Purpose: While it is well-known that elite males are faster than elite females in all Olympic-length swimming events, less is known about the age of the divergence in swimming performance between the sexes. Thus, this observational study compared swimming performance of elite male and female youths. Methods: We collected the all-time best 100 U.S....
Article
Full-text available
Force steadiness can be influenced by visual feedback as well as presence of a cognitive tasks and potentially differs with age and sex. This study determined the impact of altered visual feedback on force steadiness in the presence of a difficult cognitive challenge in young and older men and women. Forty-nine young (19–30 yr; 25 women, 24 men) an...
Article
Purpose To understand athletic performance before and after puberty, this study determined: 1) the age at which the sex difference increases among elite youth track and field athletes for running and jumping events; and 2) whether there is a sex difference in performance prior to ages associated with puberty among elite youth athletes. Methods Tra...
Article
Full-text available
OBJECTIVES/GOALS: Impaired vascular function, a subclinical marker of cardiovascular disease, has been identified in prediabetes. Dietary nitrate supplementation has been shown to improve vascular function. However, this has not been studied in prediabetes. The purpose was to determine the effects of dietary nitrate on vascular function in prediabe...
Article
Biological sex is a primary determinant of athletic human performance involving strength, power, speed, and aerobic endurance and is more predictive of athletic performance than gender. This perspective article highlights 3 key medical and physiological insights related to recent evolving research into the sex differences in human physical performa...
Article
Full-text available
Reduced heart rate variability (HRV) and fatigue are common after COVID‐19 infection and both are potentially influenced by physical activity (PA). We compared resting HRV, PA from accelerometers and questionnaires, and self‐reported fatigue in 41 COVID‐19 survivors (~8 months postinfection, 38 ± 17 years) with 41 matched controls. Differences in H...
Preprint
Full-text available
The mechanisms for the loss in limb muscle power in old (60-79 years) and very old (≥80 years) adults and whether the mechanisms differ between men and women are not well-understood. We compared maximal power of the knee extensor muscles between young, old, and very old men and women and identified the neural and muscular factors contributing to th...
Article
Full-text available
While sports medicine has traditionally focused on recovering from injury and returning athletes to sport safely after injury, there is a growing interest in the long-term health of athletes. The purpose of this scoping review was to (1) summarise the literature (methodologies and findings) on physical function, body composition and cardiometabolic...
Article
Introduction/Purpose The purpose of this study was to determine the following in persons with midportion Achilles tendinopathy (AT): 1) maximal strength and power; 2) neural drive during maximal contractions and contractile function during electrically evoked resting contractions; and 3) whether pain, neural drive, and contractile mechanisms contri...
Article
Full-text available
Introduction: The cumulative number of COVID-19 cases has surpassed 579 million globally. Symptoms during and after COVID-19 infection vary from mild cold symptoms to severe multisystem illness. Given the wide range of symptom presentations and complications post-COVID-19, the purpose of this study was to describe the lived experience of American a...
Article
Historically, low representation of women participants in exercise science and physiology studies has led to a lack of understanding in the response of women to exercise and therapeutic interventions. We hypothesized (1) the number of women authors, participants and editorial board members increased over 30 years (1991-2021) and (2) larger represen...
Article
Females demonstrate greater fatigue resistance compared to males in tasks ranging from single‐limb contractions to whole‐body exercise, including running. Many of the studies investigating sex differences in fatigability following running, however, occur after long duration, low‐intensity tasks and it is unknown whether there is a sex difference in...
Article
Full-text available
Despite activities of daily living being frequently performed simultaneously with a cognitive task, motor function is often investigated in isolation, which can hinder the applicability of findings. This brief review presents evidence that 1) performing a cognitive challenge simultaneously with a motor task can negatively impact force steadiness an...
Article
The mechanisms of increased lower limb fatigability during dynamic contractions in individuals with prediabetes are unresolved. Vascular dysfunction in people with prediabetes is a likely mechanism but has not been investigated. The purpose of this study was to determine the blood flow and muscle tissue oxygenation responses during exercise and the...
Article
The historically low representation of women as participants in exercise science and physiology research has led to a lack of understanding in the response of women to exercise and other therapeutic interventions. We hypothesize (1) the number of women authors and participants will increase over the last 30 years, and (2) a larger representation of...
Article
Introduction: The cellular mechanisms for the increased fatigability of older adults during dynamic contractions are not well understood. We recently observed that the depressive effects of fatiguing levels of acidosis (H ⁺ : pH 6.2) and inorganic phosphate (P i : 30 mM) did not differ in skeletal muscle fibers from young compared with older adults...
Article
Objective Exercise is recommended as a main treatment in fibromyalgia. However, many people have limited exercise tolerance and report exacerbated pain and fatigue during and following a bout of exercise. This study examined the local and systemic change in perceived pain and fatigue during exercise and through the 3-day recovery following isometri...
Article
There is current scientific and legal controversy about sports competition eligibility regulations for transgender athletes. In this case study, we quantified performances by an elite, transgender woman (male sex, female gender identity) college swimmer who competed in both the men's and women's NCAA categories. We also contextualized her performan...
Article
Full-text available
Changes in old age that contribute to the complex issue of an increased metabolic cost of walking (mass-specific energy cost per unit distance traveled) in older adults appear to center at least in part on changes in gait biomechanics. However, age-related changes in energy metabolism, neuromuscular function and connective tissue properties also li...
Article
Purpose: To determine if the speed-duration relationship is altered with age and sex of elite Master's runners. Methods: The world's top 10 performances for males and females in 3 events (800 m, 1500 m, and 5000 m) across 6 age groups (18-34, 40-49, 50-59, 60-69, 70-79, and 80-89 years) were analyzed from public data to establish theoretical mod...
Article
Objective: To understand the biopsychosocial dimensions of university health sciences students’ experiences during the COVID-19 pandemic. Participants: Health sciences students (n = 297) from two universities in July and August 2020. Methods: Participants completed a Web-based survey asking about depression, anxiety, physical activity, coronavirus...
Article
The cellular mechanisms for the age-related loss in muscle power output and increased fatigability during dynamic contractions remain unresolved. We recently observed that the depressive effects of fatiguing levels of acidosis (H+ : pH 6.2) and inorganic phosphate (Pi : 30 mM) did not differ in muscle fibers from young compared with old men. Howeve...
Article
Introduction: Annually, 55,000 more females than males are affected by stroke in the United States. Females also tend to experience more severe strokes with worse functional outcomes, which result in poorer health-related quality of life. Despite the marked differences in long-term recovery between males and females with stroke, little is known abo...
Preprint
Full-text available
Previous observational work from 2020 demonstrated gender-, age-, and location-related differences in mask-wearing behavior, despite the efficacy and public health messaging that emphasized face coverings in combatting the spread of COVID-19. In 2021, COVID-19 vaccinations and a corresponding change in public health policy became new considerations...
Preprint
There is current scientific and legal controversy about sports competition eligibility regulations for transgender athletes. To better understand and contextualize the effect of androgen-suppression treatment on swimming performance, we compared the gender-related differences in performance of a transgender swimmer who competed in both the male and...
Article
Resistance exercise training is a cornerstone in preventing age-related declines in muscle mass and strength, and fatigability of limb muscle is important to this adaptive response. It is unknown, however, whether fatigability and the underlying mechanisms differ between different resistance exercise protocols in young and older adults. The purpose...
Article
Full-text available
Introduction The single-leg heel raise test (SLHR) is commonly used in clinical settings to approximate plantar flexor strength, yet this is neither validated nor supported physiologically. The purposes of this study were to: determine (1) associations between SLHR repetitions, maximal plantar flexor strength, and reductions in strength; and (2) wh...
Article
There is scientific and legal controversy about recent technological advances in performance running shoes that reduce the energetic cost of running and may provide a distinct competitive advantage. To better understand the potential performance-enhancing effects of technological advancements in marathon racing shoes, we examined the finishing time...
Article
Full-text available
Aging is associated with large between-subjects variability in motor function among older adults, which can compromise identifying the mechanisms for age-related reductions in motor performance. This variability is in part explained by differences among older adults in habitual physical activity. Quantifying and accounting for physical activity lev...
Article
Full-text available
Purpose The aim of this study was to determine the local and systemic effects of isometric and concentric muscle contractions on experimental pain and performance fatigability in people with and without fibromyalgia. Methods Forty-seven fibromyalgia (FM: 51.3 ± 12.3 year) and 47 control (CON: 52.5 ± 14.7 year) participants performed submaximal iso...
Article
We have shown people with fibromyalgia experience exacerbated pain in the exercising limb up to three days following submaximal isometric and concentric exercise however, the pain response following eccentric exercise has not been investigated. This study investigated the change in experimental pain up to two days following submaximal eccentric exe...
Article
Full-text available
ABSTRACT IMPACT: Baseline presentation in AT (higher upper trapezius PPT with no difference at calf or tendon) may suggest a mechanism for persistent symptoms: with more advantageous central pain processing and no tradeoff peripherally, they may choose to continue their usual activities without regard for further damage to the affected tendon. OBJE...
Preprint
There is scientific and legal controversy about recent technological advances in performance running shoes that reduce the energetic cost of running and may provide a distinct competitive advantage. To better understand the potential performance-enhancing effects of Nikes pioneering marathon racing shoes, we examined the finishing times and racing...
Article
Full-text available
Introduction: This study quantified stroke-related changes in the following: (1) the averaged discharge rate of motor units (individually tracked and untracked) identified from high-density electromyography (HD-EMG) recordings, (2) global muscle EMG properties of the dorsiflexors during a fatiguing contraction, and the relationship between task end...
Article
Full-text available
Masks are an effective tool in combatting the spread of COVID-19, but some people still resist wearing them and mask-wearing behavior has not been experimentally studied in the United States. To understand the demographics of mask wearers and resistors, and the impact of mandates on mask-wearing behavior, we observed shoppers (n = 9935) entering re...
Article
Full-text available
New findings: What is the topic of this review? We review sex differences within physiological systems implicated in exercise performance; specifically, how they integrate to determine metabolic thresholds and fatigability. Thereafter, we discuss the implications that these sex differences might have for long-term adaptation to exercise. What adva...
Article
Full-text available
AimReduced physical function and increased risk of falls in older adults are accompanied by age-related reductions in torque development of leg muscles, although the mechanisms and potential sex differences are not understood.PurposeTo determine the mechanistic origins (neural vs. muscular) for the age-related reduction in torque development, we co...
Article
Full-text available
Key points Knee‐extensors demonstrate greater fatigue resistance in females compared to males during single‐limb and whole‐body exercise. For single‐limb exercise, the intensity–duration relationship is different between sexes, with females sustaining a greater relative intensity of exercise. This study established the power–duration relationship d...