Review Reports - Differential Effects of Resistance- and Endurance-Based Exercise Programs on Muscular Fitness, Body Composition, and Cardiovascular Variables in Young Adult Women: Contextualizing the Efficacy of Self-Selected Exercise Modalities

Round 1

Reviewer 1 Report

This manuscript uses 3 groups of young women (endurance training, resistance training, & control-no training) to attempt to determine the effects of 8-weeks of endurance or resistance exercise training on variables such as resting blood pressure, body composition, and muscular fitness. This topic has been studied in various populations; it is still of interest to look at this group of young women. However, a similar and recent paper was published (Beqa Ahmeti, G.; Idrizovic, K.; Elezi, A.; Zenic, N.; Ostojic, L. Endurance Training vs. Circuit Resistance Training: Effects on Lipid Profile and Anthropometric/Body Composition Status in Healthy Young Adult Women. Int J Environ Res Public Health 542 2020, 17, doi:10.3390/ijerph17041222) decreasing the novelty of this work. Below are specific comments about the manuscript.

Lines 41-42: Consider stating “higher than 120 mmHg…..”

Lines 43-47: Consider breaking this sentence as it contains multiple independent thoughts.

Lines 48-49: Consider re-wording to say “in terms of management of high blood pressure in different population groups.”

Line 50: Is it necessary to use an abbreviation for physical fitness? PF is used ~3x in the manuscript. It would be better to abbreviate blood pressure (BP) as it is used 41 times in the manuscript.

Lines 55-56: Consider another citation here (11) as the cited article briefly mentions skeletal muscle mass and locomotion, but is primarily focused on circadian rhythm and muscle mass.

Line 63: Same as previous comment. Is it necessary to abbreviate physical exercise?

Lines 79-80: systolic and diastolic blood pressure introduced in line 42, better to introduce the abbreviations at the initial appearance.

Line 94: “simultaneously investigating these two types of training” reads as if participants will be completing both resistance and endurance exercise, not one or the other. Re-word.

Lines 96-97: Blanket or definitive statements like this, especially when the cited authors do not make such strong conclusions, should be used cautiously. Additionally, the term “nowadays” suggests change compared to a previous measure. Is there evidence to support a decrease in physical activity for females comparing current date to previous records?

Lines 97-99: This is a gross generalization regarding a diverse group of individuals without adequate reference or explanation. Your statement assumes all women are or will be married with children. Can you provide a reference for this or is it an opinion about a perceived role of females? Are single and non-mothers included in this group? There may be relevant social and demographic factors faced by females, but they are painfully more complex than stating all women bear children and have more home duties.

Line 143: Mention pre-test guidelines for baseline measures. For the bioelectrical impedance measures specifically, were any pre-test guidelines utilized and were they followed for the post-treatment measures? Deviation from pre-test guidelines is known to alter results (https://www.nature.com/articles/ejcn2013118).

Line 143: The Tanita TBF-300 has questionable validity and high measurement error and may lack the precision to assess small changes in body composition. See:https://onlinelibrary.wiley.com/doi/full/10.1111/obr.12061. This should be listed as a limitation.

Lines 111-116: Was any information regarding participant training status recorded?

Lines 166-178: The pre-experimental training status for the participants would be beneficial to know as mentioned previously.

Lines 179-182: Did the participants sit for at least 5 minutes before the measurement of HR and BP? Blood pressure is known to be one of the most inaccurately performed measurements in clinical medicine (Am Fam Physician. 2005 Oct 1;72(7):1391-1398). As you know, the position of the patient, the size of the cuff and the deflation rate can have a sizable impact on blood pressure measurements. For the most accurate measurement, the American Heart Association recommends that the patient be relaxed and seated with legs uncrossed and back and arm supported at heart level and refrain from talking. Please state in more detail the protocols for these measurements.

Lines 185-187: Was this the only criteria used for selecting the protocol design and period? There are relevant adaptation time course points for both endurance and resistance training that could be discussed (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5983157/#:~:text=The%20adaptations%20to%20resistance%20training,4%20wk%20(Staron%20et%20al.).

Line 195: Referencing the original article with methodology for this test would be beneficial since there is some debate as to the accuracy and applicability of this measurement.

https://pubmed.ncbi.nlm.nih.gov/8912066/

Lines 211-212: What criteria were utilized to determine “optimal weights” for each exercise? Please give more detail. Were each done to failure? Did the trainers have a goal estimate of how hard the participants were training? While differences like high vs low load programming styles may not have different effects on cross-sectional area or changes in body composition it would be beneficial to know what programming techniques were implemented in this study (i.e. % of rep maximums).

(https://journals.lww.com/nsca-jscr/Fulltext/2018/06000/The_Effects_of_Moderate__Versus_High_Load.4.aspx?WT.mc_id=HPxADx20100319xMP#:~:text=Our%20results%20demonstrate%20that%20both,increase%20in%20thigh%20CSA%2C%20respectively.)

Lines 232-235: Is variables of the difference is not a term known to this reviewer. Is this percent change or percentage of the differences? If so, it might be better to use a term that is used widely. Also, subtracting both pre- and post- would not be appropriate as this would equal zero. This is no doubt just a wording problem.

Lines 243-244: SDP = SBP?

Line 249: C? You should spell out the control group as tables need to stand alone from the manuscript, so readers aren’t searching for abbreviations if they just want to look at tables and figures. This is true for all tables & figures.

Line 279: This is the first mention of nutritional diaries and there is no discussion of them in the methods section. Please add details about the diaries to the Methods and include how long dietary data were collected, how precise the measurements of food/drink, etc.

Lines 281-283: The presentation of kcals here may be confusing (at least American readers). For example, does RT: 2.353 ± 311 indicate 2,354 ± 311?

Line 321: What defines low training status for this population? This has not been discussed previously and this should be mentioned in the participant demographics.

Line 321-322: “Repeatedly repeated” – please re-word

Line 456: It is not discussed in the methods section, but was the control group given any instruction to refrain from physical activity beyond their current levels? Were there activity logs or activity monitors used for any group?

Author Response

Reviewer 1

This manuscript uses 3 groups of young women (endurance training, resistance training, & control-no training) to attempt to determine the effects of 8-weeks of endurance or resistance exercise training on variables such as resting blood pressure, body composition, and muscular fitness. This topic has been studied in various populations; it is still of interest to look at this group of young women. However, a similar and recent paper was published (Beqa Ahmeti, G.; Idrizovic, K.; Elezi, A.; Zenic, N.; Ostojic, L. Endurance Training vs. Circuit Resistance Training: Effects on Lipid Profile and Anthropometric/Body Composition Status in Healthy Young Adult Women. Int J Environ Res Public Health 542 2020, 17, doi:10.3390/ijerph17041222) decreasing the novelty of this work. Below are specific comments about the manuscript.

Response: Thank You for your review and supportive comments. We must say that we are aware that our study is not highly novel when it comes to sample of participants and training prgroams, and that previous studies (including the one you have cited; Beqa Ahmeti et al.) already reported findings of research where similar programs were evaluated, but in the manuscript we (i) tried to objectively report previous studies (including the cited one), and (ii) highlighted the difference between the here presented study and previous investigations (mainly with regard to studied variables). Also, we hope that the improvements and changes we have done in this version additionally improved the quality of the paper. For details on changes and improvements, please see following text.

Lines 41-42: Consider stating “higher than 120 mmHg….”

Response: Thank You for noticing, the text is rewritten.

Lines 43-47: Consider breaking this sentence as it contains multiple independent thoughts.

Response: The text is divided in two sentences and now states: “Pharmacological drugs are used as a standard means of lowering blood pressure and have no significant side effects. However, mainly for economic reasons, a healthy lifestyle that includes diet control, reduced cigarette and alcohol consumption, and, above all, physical exercise, is recommended as the most optimal way of disease prevention” (Please see 1st paragraoh of the Introduction)

Lines 48-49: Consider re-wording to say “in terms of management of high blood pressure in different population groups.”

Response: Thank You, the text is rewritten: “Therefore, there is an evident increase in interest about the potential efficacy of various types of physical exercise for reducing blood pressure levels in different population groups.” (Please see last sentence of the 1st para - Introduction)

Line 50: Is it necessary to use an abbreviation for physical fitness? PF is used ~3x in the manuscript. It would be better to abbreviate blood pressure (BP) as it is used 41 times in the manuscript.

Response: Thank You for noticing, the text is amended accordingly. Specifically, the PF is now not abbreviated, while BP is abbreviated.

Lines 55-56: Consider another citation here (11) as the cited article briefly mentions skeletal muscle mass and locomotion, but is primarily focused on circadian rhythm and muscle mass.

Response: Thank you, another citation was added (i.e. Mayeuf‐Louchart, A.; Staels, B.; Duez, H. Skeletal muscle functions around the clock. Diabetes, obesity and metabolism 2015, 17, 39-46)

Line 63: Same as previous comment. Is it necessary to abbreviate physical exercise?

Response: Thank You, the text is amended accordingly.

Lines 79-80: systolic and diastolic blood pressure introduced in line 42, better to introduce the abbreviations at the initial appearance.

Response: Thank You for noticing. The text is amended accordingly, and it reads: “Although the effects of resistance and endurance training vary, especially when intensity, extent, external load shape, and other training variables are considered, research has shown that both training modalities effectively reduce SBP and DBP.” (Please see 1^stparagraph in the Introduction section).

Line 94: “simultaneously investigating these two types of training” reads as if participants will be completing both resistance and endurance exercise, not one or the other. Re-word.

Response: Thank You. The text is now rewritten and states: “Irrespective of the fact that positive effects of both endurance- and resistance-based training are frequently reported, there is an evident lack of research simultaneously investigating differential effects of these two types of training with regard to their potential influence on fitness and health status in young women.”

Response: The cited study (Aleksovska, K.; Puggina, A.; Giraldi, L.; Buck, C.; Burns, C.; Cardon, G.; Carlin, A.; Chantal, S.; Ciarapica, D.; Colotto, M., et al. Biological determinants of physical activity across the life course: a "Determinants of Diet and Physical Activity" (DEDIPAC) umbrella systematic literature review. Sports Med Open 2019, 5, 2, doi:10.1186/s40798-018-0173-9) is systematic review that indicates, among other, that being male has more positive association to physical activity. However, we amended the text: “From our perspective, this is particularly important because of the known fact that being a male has significant higher positive association with involvement in PE”

Response: We couldn’t agree more! Definitively, the factors influencing demographic factors faced by women are far more complex than we stated. However, we just wanted to point to “general fact” that when comparing genders of the same age and “social status”, women have less free time than men (at least authors share such opinion). In this version of the manuscript we tried to be more cautious and text reads: “For example, if we compare employed men and women, authors of the study are of the opinion that women at the same time face greater parental responsibilities and home duties than men (Gordon, J. R., & Whelan-Berry, K. S. (2005). Contributions to family and household activities by the husbands of midlife professional women. Journal of Family Issues, 26(7), 899-923).” (Please see penultimate paragraph in Introduction section for more details).

Response: Thank You, we forgot to highlight the guidelines. The text is now added: “These measurements were done in the morning and the participants were instructed not to eat before.”

Line 143: The Tanita TBF-300 has questionable validity and high measurement error and may lack the precision to assess small changes in body composition. See: https://onlinelibrary.wiley.com/doi/full/10.1111/obr.12061. This should be listed as a limitation.

Response: Thank You. The text is amended accordingly and now states: “One of the limitations of the study is use of Tanita TBF-300 for body composition assessments, which has questionable validity and measurement error and may lack the precision to assess small changes in body composition [63]. However, we believe that with the same measurement protocol and pre-test guidelines, measurement errors were minimized.” (Please see Limitations and Strengths subsection).

Lines 111-116: Was any information regarding participant training status recorded?

Response: Thank You, the sentence about their training status is added: “The participants were mostly university students and did not have any previous experience regarding physical exercise and training.”

Lines 166-178: The pre-experimental training status for the participants would be beneficial to know as mentioned previously.

Response: Please look at the previous comment.

Lines 179-182: Did the participants sit for at least 5 minutes before the measurement of HR and BP? Blood pressure is known to be one of the most inaccurately performed measurements in clinical medicine (Am Fam Physician. 2005 Oct 1;72(7):1391-1398). As you know, the position of the patient, the size of the cuff and the deflation rate can have a sizable impact on blood pressure measurements. For the most accurate measurement, the American Heart Association recommends that the patient be relaxed and seated with legs uncrossed and back and arm supported at heart level and refrain from talking. Please state in more detail the protocols for these measurements.

Response: Thank You for your comment. The text is amended accordingly:” The participants were in a seated position, with parallel legs and their back and arm supported at the heart level. They were instructed to be in relaxed position and to avoid talking.” (Please see end of the Variables subsection).

Response: Thank You for your comment. We are aware of relevant adaptation time for each type of training. However, based on the experience from one of the authors that works in the specific gym where training programs were performed, we took 8-week period as most suitable as after that time, large number of females starts to drop-out.

Line 195: Referencing the original article with methodology for this test would be beneficial since there is some debate as to the accuracy and applicability of this measurement.

https://pubmed.ncbi.nlm.nih.gov/8912066/

Response: Thank You. The reference was changed.

Response: Thank You for your comment. More details are provided and the text now reads: “The participants performed three sets with progressive load increase and did until failure in the final set.”

Response: Thank you for noticing it. Actually, we missed to report that we calculated differences between pre- and post-measurement for each participant and each outcome variable. It is now specified in more details, and text reads: “In order to evaluate the associations between the obtained changes, we calculated the variables of the differences (VD) for each observed anthropometric/body composition, muscular fitness, and cardiovascular parameter (outcomes) by subtracting the pre- and post-test results for each outcome and each participant. Consequently, bigger numerical value presented greater change in studied outcome.” (please see end of Statistics subsection)

Lines 243-244: SDP = SBP?

Response: Thank You for noticing. The abbreviation is rewritten.

Response: The text is amended accordingly.

Response: Thank You for noticing. The text is added in methods part: “At the beginning and at the end of the study the participants were asked to write their nutrition intake in food diaries, 3 days at the beginning and at the end of the study, and the data was later analyzed with nutritional tables and software.” (please see end of Variables subsection)

Lines 281-283: The presentation of kcals here may be confusing (at least American readers). For example, does RT: 2.353 ± 311 indicate 2,354 ± 311?

Response: The data is amended accordingly.

Line 321: What defines low training status for this population? This has not been discussed previously and this should be mentioned in the participant demographics.

Response: Thank You for your comment. The training status of participants was additionally explained as mentioned in previous comments (please see 1^stparagraph in the Methods section).

Line 321-322: “Repeatedly repeated” – please re-word

Response: The text is amended accordingly and now states: “A possible explanation may be found in the fact that the sample consisted of women of low training status, so even the relatively low external load, but repetitively repeated performed due to running, caused certain muscle adaptations, mostly in the lower extremities.”

Response: Thank You for your comment. The text is amended accordingly: “However, since they were not instructed about performing some type of training, and they did not do it so systematically, they could not achieve improvements in the other measured variables.”

Thank you for your suggestions and comments.

Staying at your disposal

Reviewer 2 Report

To the Authors

The study of Versic et al (1245575) investigated the effects of resistance training and endurance training and on anthropometric/body build indices, blood pressure, and muscular fitness in 17 healthy young women who participated in a self-preferred program. The authors reported a similar improvement in body build (increase in lean body mass and decrease in body fat percentage), resting heart rate, and flexibility in both of the exercise groups, with no significant changes in the control group. Resistance training improved the participants’ strength and force capacities to a greater extent than ET. Blood pressure showed a trend of improvement in both of the training groups, but without statistically significant pre- to post-changes. The study is well designed and nicely executed. There are, however, few data interpretational issues that authors need to clarify and subsequently address in their manuscript.

Major Points

The practical considerations are not so highlighted.

Specific Points

The following points need to be addressed:

Introduction:

There is a clear rationale of this study and a well-tested hypothesis. However, the authors have to highlight the practical considerations of this research.

Paragraph 1, line 42: Please use mmHg instead of mmHG.

Materials and Methods.

Participants and design of the study

All participants were female. Please provide information about whether the phase of the menstrual cycle was controlled before and after the exercise training program evaluations and indicated the phase of the menstrual cycle. The cyclic variations of estrogen and progesterone levels during a menstrual cycle affect some variables of physical fitness.

Variables

Paragraph 2, lines 142-143: Body composition was assessed through a bioimpedance device (Tanita). Please provide information about whether all participants followed the same instruction before and after the exercise training program for accurate body composition measurements.
Which are the interclass correlation coefficient (ICC) for test-retest reliability for body composition evaluation?
Please provide information about the interclass correlation coefficient for test-retest reliability for all assessments (flexibility, strength).

Training programs:

All participants finished the study or where was a dropout?
- What was the attendance rate for training groups? Please provide the information.
- The participation in recreational activities of the control group was controlled?
- Did you repeat the Conconi test after the exercise training program to see any differences in aerobic capacity across groups?

Results

You state in the Method section that more details on participants are given in the Results section. Please be more specific.
The authors should report the conconi test results as an index of the participant’s physical level at baseline.
Where were any differences across groups (control, endurance, and resistance program) at baseline?

Discussion

It is well written without raising major concerns.

Paragraph 1, line 287: Please use body composition instead of body build, throughout the manuscript.
Paragraph 2, line 294: ‘changes ere evidenced’ I think that something is missing.

Author Response

REVIEWER 2

Response: Thank you for your review and support. We tried to follow all your comments and amended the manuscript accordingly. Please see following text for details on amendments.

Major Points

The practical considerations are not so highlighted.

Response: Thank You. The text is amended and now states: “Therefore, this study aimed to determine the effects of eight-week exercise programs on anthropometric/body composition indices, BP, and muscular fitness in apparently healthy young women. These information will give clear practical implications for planning and optimizing the training regimes in this population in order to achieve morphological, health and fitness goals. We hypothesized that both programs would induce positive changes on the studied variables, with: (i) superior effects of resistance training on muscular fitness capacities (strength, flexibility, and dynamometric force), and (ii) superior effects of endurance training on BP and anthropometric/body composition status” (Please see last paragraph in Introduction section for more details).

Specific Points

The following points need to be addressed:

Introduction:

There is a clear rationale of this study and a well-tested hypothesis. However, the authors have to highlight the practical considerations of this research.

Response: Thank You. Please see the previous comment.

Paragraph 1, line 42: Please use mmHg instead of mmHG.

Response: The text is amended accordingly.

Materials and Methods.

Participants and design of the study

All participants were female. Please provide information about whether the phase of the menstrual cycle was controlled before and after the exercise training program evaluations and indicated the phase of the menstrual cycle. The cyclic variations of estrogen and progesterone levels during a menstrual cycle affect some variables of physical fitness.

Response: Thank You for your comment. Unfortunately, we did not control phases of menstrual cycle before and after the exercise program. However, this is added in the limitations section and the text reads: “The menstrual cycle was not controlled before and after the training program. Since the cyclic variations of estrogen and progesterone levels during a menstrual cycle affect some variables of physical fitness this could be viewed as study limitation.” (please see Limitations and Strengths subsection).

Variables

Paragraph 2, lines 142-143: Body composition was assessed through a bioimpedance device (Tanita). Please provide information about whether all participants followed the same instruction before and after the exercise training program for accurate body composition measurements.

Response: Thank You for your comment. Additional information is provided about pre-test guidelines: “These measurements were done in the morning and the participants were instructed not to eat before. “

Which are the interclass correlation coefficient (ICC) for test-retest reliability for body composition evaluation? Please provide information about the interclass correlation coefficient for test-retest reliability for all assessments (flexibility, strength).

Response: The ICC values for tests done throughout 2 and more testing trials are presented (i.e. “The reliability of the measurement indicated throughout intra-class coefficient of the correlation (ICC) for anthropometric/body composition variables on the basis of test-retest protocol ranged from 0.96 (for BH), to 0.82 (for LBM and BF% measurement”; please see 2nd paragraph of the Variables subsection.)

Training programs:

All participants finished the study or where was a dropout?

What was the attendance rate for training groups? Please provide the information.

The participation in recreational activities of the control group was controlled?

Did you repeat the Conconi test after the exercise training program to see any differences in aerobic capacity across groups?

Response: In this version of the manuscript we reported details about drop-out rates and attendance are added. Text reads: “Initially, groups consisted of more participants (ET = 21; RT = 22, and C = 20), but only those who participated in >80% of training sessions (for training groups) both testing sessions (all groups), and who were not involved in some physical exercising during the study period (C group) were observed in the study, resulting in drop-out rate of 11%.” (please see end of 1st paragraph of the Methods section).

Conconi test was not repeated as a measure of aerobic fitness in ET groups, but only as a method of evaluation of status. Initial results are now indicated, and text reads: „During the “null week” of the experiment (Figure 1), the participants in the ET group conducted a Conconi test in order to estimate their anaerobic threshold (pre-testing value of 154 ± 11 beats per minute).” Please see 2nd paragraph of the Training programs subsection. Thank you!

Results

You state in the Method section that more details on participants are given in the Results section. Please be more specific. The authors should report the conconi test results as an index of the participant’s physical level at baseline. Where were any differences across groups (control, endurance, and resistance program) at baseline?

Response: Unfortunately, in this study we did not compare results of the aerobic endurance among groups. Specifically, Conconi test was done exclusively in ET group in order to program their training routine. However, we must agree that this should be observed as limitation of the study and it is specified in the revised version. Text reads. “Finally, this study lacks comparison of pre-testing between group differences in aerobic capacity. Therefore, there is a certain possibility that initial differences between groups at least partially influenced even the training effects.” (please see Limitations and Strengths subsection)

Discussion

It is well written without raising major concerns.

Paragraph 1, line 287: Please use body composition instead of body build, throughout the manuscript.

Response: Thank You, the text is amended accordingly.

Paragraph 2, line 294: ‘changes ere evidenced’ I think that something is missing.

Response: Thank You for noticing. Typing error is amended.

Thank you for your suggestions and comments.

Staying at your disposal

Reviewer 3 Report

I have read with great interest this paper where the Authors report valuable data regarding the self-selected exercise effect on muscular and cardiovascular parameters.

For such a reason the article should be suitable for publication, nevertheless a minor revision is needed.

Please define more in details in the methods section what do you mean with “in apparently healthy young women”:

are the subjects physically active (in other words do they perform exercise regularly and if yes how often)?
or are they healthy but sedentary?

This is an important point that can influence your conclusions and perhaps should be also discuss.

Author Response

REVIEWER 3

I have read with great interest this paper where the Authors report valuable data regarding the self-selected exercise effect on muscular and cardiovascular parameters.

For such a reason the article should be suitable for publication, nevertheless a minor revision is needed.

Please define more in details in the methods section what do you mean with “in apparently healthy young women”: are the subjects physically active (in other words do they perform exercise regularly and if yes how often)? or are they healthy but sedentary?

This is an important point that can influence your conclusions and perhaps should be also discuss.

Response: Thank You for your comment. The details about participants training status are added: “The participants were mostly university students and did not have any previous experience regarding physical exercise and training.” (Please see Methods section for more details.)

Thank you for your suggestions and comments.

Staying at your disposal!