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Papers by ELIZABETH OROZCO
Journal of Rehabilitation Practices and Research
Background: Chronic pain is commonly reported in people living with the human immunodeficiency vi... more Background: Chronic pain is commonly reported in people living with the human immunodeficiency virus (HIV). Chronic pain has been linked to decreased quality of life, mobility impairments, and increased risk of cardiovascular complications in the general population. Therefore, the purpose of this study was to determine the relationship between chronic pain and cardiovascular and locomotor function in people living with HIV (PLWH). Subjects: A total of 291 participants were enrolled in this study, 251 without chronic pain (non-CP), and 40 participants with chronic pain (CP). Both groups were comparable in terms of age and years of diagnosis. Methods: Data was collected retrospectively from a community-based exercise program in San Juan, Puerto Rico from 2000-2020. The cardiovascular and motor components of this study were collected using the Ross submaximal cardiovascular test. The presence of chronic pain and Cd4 count was collected by interview and results from the participants’ mo...
International Journal of Physical Education, Fitness and Sports, May 3, 2022
Motorized treadmills and weighted sleds are employed in clinical settings to improve lower extrem... more Motorized treadmills and weighted sleds are employed in clinical settings to improve lower extremity strength, power, and endurance. However, little is known about how the spatio-temporal parameters compare when walking on an even surface walkway, walking on a treadmill, or pushing a sled. This study aimed to examine the variations in spatial and temporal gait parameters when walking on an even surface walkway (EW), on a treadmill (TW), and while pushing a sled (SP). Forty healthy subjects participated in this pilot study. The mean age and BMI of all participants were 24.39 (± 2.86) years and 68.26 (± 13.92) kg/m^2, respectively. Spatio-temporal parameters were gathered using the Mobility Lab ADPM software and six sensors containing accelerometers and gyroscopes. Participants were directed to walk at a normal and comfortable speed for 7 m on an even surface walkway for two trials. Next, the subjects walked on the treadmill for two trials at a speed based on age. For males aged <30 and females 20-40 years of age, the speed was 1.3 m/s. While for males aged 30 or older, the speed was set to 1.4 m/s. Finally, participants were instructed to walk at their normal pace while pushing a 60 lb sled for 9.1 meters (m). Treadmill walking provoked a significant increase in temporal variables, whereas pushing a sled significantly reduced the temporal variables. Treadmill walking resulted in a decrease in double limb support time and an increase in single-limb support time compared with even surface walking. Although cadence was greater when walking on a treadmill versus an even surface walkway, the difference may be attributed to a fixed speed on the treadmill, which was determined by age. Treadmill gait training is recommended for subjects that could benefit from an increase single limb support time to improve dynamic balance such as Parkinson patients. On the other hand, for those participants that dynamic activities are challenging, such as concussion and vestibular patients, pushing the sled will slow down gait parameters allowing gait training with an added resistance benefit. Finally, it has been proposed that further investigation should focus on the differences in lower extremity muscle activation and recruitment patterns under various walking conditions.
European Journal of Sport Sciences
Treadmill walking is a popular form of exercise that offers many benefits to its users, such as i... more Treadmill walking is a popular form of exercise that offers many benefits to its users, such as improvements in cardiovascular health and gait patterns. Few research studies have explored muscle activation of various lower extremity joints at different levels of inclination on a treadmill. Therefore, this study aims to further characterize muscle activation during gait in healthy individuals in response to changes in treadmill inclination at a constant speed. Twenty healthy participants (24.5 ± 4.3 years of age) were recruited for this study. Participants were instructed to walk on a treadmill at six different inclines (0%, 3%, 6%, 9%, 12%, and 15%) while maintaining a constant speed of 3.4 mph. Muscle activation of the tibialis anterior (TA), gastrocnemius (GA), gluteus maximus (GMAX), gluteus medius (GMED), vastus medialis (QUADS), and biceps femoris (HS) were collected using surface EMG. There were slight differences in muscle activation between the muscle groups during the vario...
Journal of Sports Research, 2021
Usually, dual cognitive tasks require additional attention to maintain postural control during st... more Usually, dual cognitive tasks require additional attention to maintain postural control during standing and walking. In certain pathologies or injuries, dual cognitive tasks, such as walking and speaking, can challenge the balance system, making certain gait deficiencies more apparent. The issue is identifying normal gait changes compared to gait impairments to understand better the impact cognitive tasks have on gait mechanics. Purpose: To identify changes in temporospatial gait parameters in healthy young adults while walking and performing a cognitive task. Methods: Thirty-four healthy young adults participated in this study. We collected gait parameters with six gyroscopes and accelerometers (distributed on all limbs and trunk) during the 7-meter walk test. Two trials were performed with just walking at a self-selected pace (single task). Then, the participant was asked to perform a cognitive task by counting backward by three from 100 while walking for 7m for two more trials (dual cognitive task). Results: Dual cognitive tasks provoked significant adaptations (p<.05) in gait parameters, such as increased double limb support time and stance phase with a reduction in single limb support time and swing phase. Increase the length of the walking cycle by decreasing the cadence and speed of walking speed. In addition, an increase in mediolateral postural sway, first-step initiation time, and trunk range of motion was observed. Conclusion: Dual cognitive tasks can cause normal alterations in the gait's dynamic component and variations in walking initiation. We recommend studying neuromuscular modification, such as changes in muscle activation, during dual cognitive tasks. Contribution/Originality: The paper's primary contribution is finding gait and postural adaptations to dual cognitive tasks in healthy young adults. Specifically, this study identified anticipatory postural adaptations that could be used as a foundation to assess and create treatment interventions in those with balance impairments.
Background: Falls due to altered balance is a worldwide health concern. Previous investigations h... more Background: Falls due to altered balance is a worldwide health concern. Previous investigations have delved into the effect of dual-tasking balance and gait (kinematic alteration) because of the increased attentional loads demanded from the brain. In addition, impaired neuromuscular patterns could additionally contribute to gait alterations and increased fall risk. This study aims to identify the muscle activation pattern of lower limb musculature during single and dual tasks in healthy young adults. Methods: Thirty-four participants (9 males and 25 females, mean age of 24.88 ± 5.13) completed two 7-meter level ground walk trials under singular then dual tasks. We implemented an amplitude analysis filter to normalize EMG amplitude data to obtain a percentage of the amplitude (0-100%) and timing amplitude. Results: The ANOVA analysis revealed no considerable distinction in muscle activity amplitude among dual and single cognitive tasks (p ≥ 0.05). When assessing the activation patter...
Medicine & Science in Sports & Exercise, 2019
People living with human immunodeficiency virus (HIV) withstand various complications that negati... more People living with human immunodeficiency virus (HIV) withstand various complications that negatively impact multiple body systems such as cardiovascular and immune systems. Exercise therapy has been found to sustain and even improve the health of people living with HIV. However, the advantages of a community-based exercise program targeting Hispanic-Latinos with HIV are yet to be studied. Purpose: The study aimed to identify the effects of a communitybased exercise program on immunity (CD4 count), cardiovascular fitness, and muscular fitness in Hispanic-Latino individuals living with HIV. Subjects and Methods: Twenty-five adults with HIV (ages 55.6 ± 9.6 years) participated in this study. The current inquiry was a retrospective cohort study that used data collected from individuals who participated in a community organization, known as La Perla de Gran Precio, in San Juan, Puerto Rico. A certified personal trainer performed all exercise testing. Cardiovascular fitness was assessed using the Ross Submaximal Treadmill Test. Strength was measured by determining the 1-repetition maximum (1-RM) for bench press and leg press. Muscular endurance was assessed by measuring the maximum number of push-ups and sit-ups that could be completed in 1 minute. Flexibility was tested using the Sit and Reach Test. Immune function (CD4 count and viral load) was measured by asking participants to bring a copy of their most recent lab results to each fitness evaluation. The same assessment was administered three more times to track participants' progress over a year. Results: There was a significant difference in CD4 counts over the four evaluations, F (3,69)=6.947, p<.001. However, results from Freidman's ANOVA also revealed a significant reduction in heart rate (p=.005) during the submaximal exercise test. Conclusion: Participation in community-based exercise programs can help improve immune function and cardiovascular fitness in people with HIV. Therefore, people with HIV should engage in regular exercise and be introduced to community/recreational programs.
Journal of Human Sport and Exercise, 2019
Diabetes and neuropathy have been linked to postural instability. Aims: The purpose of this study... more Diabetes and neuropathy have been linked to postural instability. Aims: The purpose of this study is to determine how each system involved in balance is affected when challenged in a static standing posture. The goal was to identify postural instability by measuring balance through the amount of sway and weight bearing distribution in non-neuropathic controlled type II diabetics. Methods: Twelve participants (five males and seven females) with controlled type II diabetes mellitus and no history of peripheral neuropathy (Non-PN cDMII) formed the diabetic group, whereas eighteen participants (7 males and 11 females) without type II diabetes formed the control group. The exclusion criteria was applied via a series of screening tests (Berg Balance Scale, Five Times Sit To Stand Test, Functional Reach Test and Monofilament Test). Postural stability and weight distribution during quiet standing were measured using a Tekscan Matscan pressure mat, which measured the amount of sway and weight distribution. Static postural control was evaluated during eight sensory conditions that perturbed or stimulated the visual, proprioceptive, and vestibular systems. Results: Postural control was found to be significantly deficient when the vestibular system was stimulated, whereas the proprioceptive system was perturbed. After the data analysis, there was a significant difference in antero-posterior sway (P=0.05) with the following tasks: eyes open with head movements on an unstable surface, and eyes closed with head movements on a firm surface. Conclusions: The results revealed that the experimental group with type II diabetes had greater postural instability when compared to the control group during tasks with the vestibular system on an unstable surface. This demonstrates that, due to their deficits, individuals with non-PN cDMII are unable to maintain their balance when the vestibular and proprioceptive
F1000Research, 2018
Background: Patients with diabetes have been shown to suffer from increased fall risk. Research s... more Background: Patients with diabetes have been shown to suffer from increased fall risk. Research shows that this risk is higher on irregular surfaces. Existing studies evaluate gait on irregular surfaces, such as stairs, asphalt, grass and stones. This study evaluates gait parameters in individuals with diabetes mellitus type II (DMII) with no history of peripheral neuropathy, while ascending and descending a ramp at an imposed speed, and compares them with healthy controls. Methods: Fifteen healthy volunteer participants and fifteen participants with DMII and no peripheral neuropathy (females and males) between the ages of 40-65 were recruited for this study. Participants walked three times at 100 bpm while ascending and descending a wooden ramp. Temporospatial and kinematic parameters were analyzed. Results: We observed minimal changes in temporospatial and kinetic parameters in people with controlled DMII with no evidence of peripheral neuropathy. Conclusion: Focusing on individu...
Journal of Rehabilitation Practices and Research
Background: Chronic pain is commonly reported in people living with the human immunodeficiency vi... more Background: Chronic pain is commonly reported in people living with the human immunodeficiency virus (HIV). Chronic pain has been linked to decreased quality of life, mobility impairments, and increased risk of cardiovascular complications in the general population. Therefore, the purpose of this study was to determine the relationship between chronic pain and cardiovascular and locomotor function in people living with HIV (PLWH). Subjects: A total of 291 participants were enrolled in this study, 251 without chronic pain (non-CP), and 40 participants with chronic pain (CP). Both groups were comparable in terms of age and years of diagnosis. Methods: Data was collected retrospectively from a community-based exercise program in San Juan, Puerto Rico from 2000-2020. The cardiovascular and motor components of this study were collected using the Ross submaximal cardiovascular test. The presence of chronic pain and Cd4 count was collected by interview and results from the participants’ mo...
International Journal of Physical Education, Fitness and Sports, May 3, 2022
Motorized treadmills and weighted sleds are employed in clinical settings to improve lower extrem... more Motorized treadmills and weighted sleds are employed in clinical settings to improve lower extremity strength, power, and endurance. However, little is known about how the spatio-temporal parameters compare when walking on an even surface walkway, walking on a treadmill, or pushing a sled. This study aimed to examine the variations in spatial and temporal gait parameters when walking on an even surface walkway (EW), on a treadmill (TW), and while pushing a sled (SP). Forty healthy subjects participated in this pilot study. The mean age and BMI of all participants were 24.39 (± 2.86) years and 68.26 (± 13.92) kg/m^2, respectively. Spatio-temporal parameters were gathered using the Mobility Lab ADPM software and six sensors containing accelerometers and gyroscopes. Participants were directed to walk at a normal and comfortable speed for 7 m on an even surface walkway for two trials. Next, the subjects walked on the treadmill for two trials at a speed based on age. For males aged <30 and females 20-40 years of age, the speed was 1.3 m/s. While for males aged 30 or older, the speed was set to 1.4 m/s. Finally, participants were instructed to walk at their normal pace while pushing a 60 lb sled for 9.1 meters (m). Treadmill walking provoked a significant increase in temporal variables, whereas pushing a sled significantly reduced the temporal variables. Treadmill walking resulted in a decrease in double limb support time and an increase in single-limb support time compared with even surface walking. Although cadence was greater when walking on a treadmill versus an even surface walkway, the difference may be attributed to a fixed speed on the treadmill, which was determined by age. Treadmill gait training is recommended for subjects that could benefit from an increase single limb support time to improve dynamic balance such as Parkinson patients. On the other hand, for those participants that dynamic activities are challenging, such as concussion and vestibular patients, pushing the sled will slow down gait parameters allowing gait training with an added resistance benefit. Finally, it has been proposed that further investigation should focus on the differences in lower extremity muscle activation and recruitment patterns under various walking conditions.
European Journal of Sport Sciences
Treadmill walking is a popular form of exercise that offers many benefits to its users, such as i... more Treadmill walking is a popular form of exercise that offers many benefits to its users, such as improvements in cardiovascular health and gait patterns. Few research studies have explored muscle activation of various lower extremity joints at different levels of inclination on a treadmill. Therefore, this study aims to further characterize muscle activation during gait in healthy individuals in response to changes in treadmill inclination at a constant speed. Twenty healthy participants (24.5 ± 4.3 years of age) were recruited for this study. Participants were instructed to walk on a treadmill at six different inclines (0%, 3%, 6%, 9%, 12%, and 15%) while maintaining a constant speed of 3.4 mph. Muscle activation of the tibialis anterior (TA), gastrocnemius (GA), gluteus maximus (GMAX), gluteus medius (GMED), vastus medialis (QUADS), and biceps femoris (HS) were collected using surface EMG. There were slight differences in muscle activation between the muscle groups during the vario...
Journal of Sports Research, 2021
Usually, dual cognitive tasks require additional attention to maintain postural control during st... more Usually, dual cognitive tasks require additional attention to maintain postural control during standing and walking. In certain pathologies or injuries, dual cognitive tasks, such as walking and speaking, can challenge the balance system, making certain gait deficiencies more apparent. The issue is identifying normal gait changes compared to gait impairments to understand better the impact cognitive tasks have on gait mechanics. Purpose: To identify changes in temporospatial gait parameters in healthy young adults while walking and performing a cognitive task. Methods: Thirty-four healthy young adults participated in this study. We collected gait parameters with six gyroscopes and accelerometers (distributed on all limbs and trunk) during the 7-meter walk test. Two trials were performed with just walking at a self-selected pace (single task). Then, the participant was asked to perform a cognitive task by counting backward by three from 100 while walking for 7m for two more trials (dual cognitive task). Results: Dual cognitive tasks provoked significant adaptations (p<.05) in gait parameters, such as increased double limb support time and stance phase with a reduction in single limb support time and swing phase. Increase the length of the walking cycle by decreasing the cadence and speed of walking speed. In addition, an increase in mediolateral postural sway, first-step initiation time, and trunk range of motion was observed. Conclusion: Dual cognitive tasks can cause normal alterations in the gait's dynamic component and variations in walking initiation. We recommend studying neuromuscular modification, such as changes in muscle activation, during dual cognitive tasks. Contribution/Originality: The paper's primary contribution is finding gait and postural adaptations to dual cognitive tasks in healthy young adults. Specifically, this study identified anticipatory postural adaptations that could be used as a foundation to assess and create treatment interventions in those with balance impairments.
Background: Falls due to altered balance is a worldwide health concern. Previous investigations h... more Background: Falls due to altered balance is a worldwide health concern. Previous investigations have delved into the effect of dual-tasking balance and gait (kinematic alteration) because of the increased attentional loads demanded from the brain. In addition, impaired neuromuscular patterns could additionally contribute to gait alterations and increased fall risk. This study aims to identify the muscle activation pattern of lower limb musculature during single and dual tasks in healthy young adults. Methods: Thirty-four participants (9 males and 25 females, mean age of 24.88 ± 5.13) completed two 7-meter level ground walk trials under singular then dual tasks. We implemented an amplitude analysis filter to normalize EMG amplitude data to obtain a percentage of the amplitude (0-100%) and timing amplitude. Results: The ANOVA analysis revealed no considerable distinction in muscle activity amplitude among dual and single cognitive tasks (p ≥ 0.05). When assessing the activation patter...
Medicine & Science in Sports & Exercise, 2019
People living with human immunodeficiency virus (HIV) withstand various complications that negati... more People living with human immunodeficiency virus (HIV) withstand various complications that negatively impact multiple body systems such as cardiovascular and immune systems. Exercise therapy has been found to sustain and even improve the health of people living with HIV. However, the advantages of a community-based exercise program targeting Hispanic-Latinos with HIV are yet to be studied. Purpose: The study aimed to identify the effects of a communitybased exercise program on immunity (CD4 count), cardiovascular fitness, and muscular fitness in Hispanic-Latino individuals living with HIV. Subjects and Methods: Twenty-five adults with HIV (ages 55.6 ± 9.6 years) participated in this study. The current inquiry was a retrospective cohort study that used data collected from individuals who participated in a community organization, known as La Perla de Gran Precio, in San Juan, Puerto Rico. A certified personal trainer performed all exercise testing. Cardiovascular fitness was assessed using the Ross Submaximal Treadmill Test. Strength was measured by determining the 1-repetition maximum (1-RM) for bench press and leg press. Muscular endurance was assessed by measuring the maximum number of push-ups and sit-ups that could be completed in 1 minute. Flexibility was tested using the Sit and Reach Test. Immune function (CD4 count and viral load) was measured by asking participants to bring a copy of their most recent lab results to each fitness evaluation. The same assessment was administered three more times to track participants' progress over a year. Results: There was a significant difference in CD4 counts over the four evaluations, F (3,69)=6.947, p<.001. However, results from Freidman's ANOVA also revealed a significant reduction in heart rate (p=.005) during the submaximal exercise test. Conclusion: Participation in community-based exercise programs can help improve immune function and cardiovascular fitness in people with HIV. Therefore, people with HIV should engage in regular exercise and be introduced to community/recreational programs.
Journal of Human Sport and Exercise, 2019
Diabetes and neuropathy have been linked to postural instability. Aims: The purpose of this study... more Diabetes and neuropathy have been linked to postural instability. Aims: The purpose of this study is to determine how each system involved in balance is affected when challenged in a static standing posture. The goal was to identify postural instability by measuring balance through the amount of sway and weight bearing distribution in non-neuropathic controlled type II diabetics. Methods: Twelve participants (five males and seven females) with controlled type II diabetes mellitus and no history of peripheral neuropathy (Non-PN cDMII) formed the diabetic group, whereas eighteen participants (7 males and 11 females) without type II diabetes formed the control group. The exclusion criteria was applied via a series of screening tests (Berg Balance Scale, Five Times Sit To Stand Test, Functional Reach Test and Monofilament Test). Postural stability and weight distribution during quiet standing were measured using a Tekscan Matscan pressure mat, which measured the amount of sway and weight distribution. Static postural control was evaluated during eight sensory conditions that perturbed or stimulated the visual, proprioceptive, and vestibular systems. Results: Postural control was found to be significantly deficient when the vestibular system was stimulated, whereas the proprioceptive system was perturbed. After the data analysis, there was a significant difference in antero-posterior sway (P=0.05) with the following tasks: eyes open with head movements on an unstable surface, and eyes closed with head movements on a firm surface. Conclusions: The results revealed that the experimental group with type II diabetes had greater postural instability when compared to the control group during tasks with the vestibular system on an unstable surface. This demonstrates that, due to their deficits, individuals with non-PN cDMII are unable to maintain their balance when the vestibular and proprioceptive
F1000Research, 2018
Background: Patients with diabetes have been shown to suffer from increased fall risk. Research s... more Background: Patients with diabetes have been shown to suffer from increased fall risk. Research shows that this risk is higher on irregular surfaces. Existing studies evaluate gait on irregular surfaces, such as stairs, asphalt, grass and stones. This study evaluates gait parameters in individuals with diabetes mellitus type II (DMII) with no history of peripheral neuropathy, while ascending and descending a ramp at an imposed speed, and compares them with healthy controls. Methods: Fifteen healthy volunteer participants and fifteen participants with DMII and no peripheral neuropathy (females and males) between the ages of 40-65 were recruited for this study. Participants walked three times at 100 bpm while ascending and descending a wooden ramp. Temporospatial and kinematic parameters were analyzed. Results: We observed minimal changes in temporospatial and kinetic parameters in people with controlled DMII with no evidence of peripheral neuropathy. Conclusion: Focusing on individu...