**4. Conclusions and final ideas**

The comparison between men and women in labor terms is not fair. Both genders perform different tasks, with different expositions, different patterns of rotation, and different resources to face the work. Probably, both gender are based on a differents patterns but complementaries.

Several studies show a major biomechanical affectation in female group than male group of workers in a great variety of industrial tasks [26]. But at least performing repetitive tasks involving a prehensile effort of less than 15 N or manual loads of less than 50 Gr per repetition, these results are not caused by a gender weakness but a higher-risk exposition in both ways: in short-term time, because women perform more repetitions monthly than men; and in long-term time, because they can support repetitive loads of work for longer time, so they remain for longer time in the repetitive job workplaces.

These results are consistent with Tomaskovic-Devey [27], which results show that exposure to repetitive work is more frequent among working women; and it is consistent with Kilbom [28], whose results show that a greater proportion of women than men suffer problems especially in the upper limbs; finding out that occupations at high risk of musculoskeletal problems in upper limbs, the majority had a mostly female workforce. Results are consistent with NIOSH too, showing that "female gender was a significant predictor of tendinitis."

Although the incidence and prevalence for some authors have not yet been established for De Quervain's disease, some report prevalence between 2.5 and 8% in women of the total working population. Women are more frequently affected than men (8:1 ratio), and the age of onset is between 30 and 60 years [29].

Hobby [30] tested the effects of age and gender on the results of surgery for carpal tunnel release in 97 patients with a diagnosis of CTS. Evaluation was performed before the release and 6 months after surgery. Women reported more symptoms and postoperative disability than men.

These researches show that repetitive work is more frequent among feminized positions, and musculoskeletal disorders in upper limbs are more frequent, pointing to an obvious correlation. But these studies do not inquire about the technical justifications for these phenomena and only describe them. This chapter is not intended to delve into the results of prehensile strength, acceleration of movements, or comparative productivity between genders (which are found in more detail in another article by the authors [25]) but to express conclusions that may be useful to understand probable causes of the phenomena studied and thus explore measures that minimize the effects of repetitive work in women.

This study does not show a greater biomechanical resistance of the feminine articular systems in relation to the masculine ones, but it shows a greater "muscular intelligence" in the accomplishment of the repetitive tasks, which acts as a protective factor and enhances productivity. This feature is based on energy savings and biomechanical resources in each technical action, applying the pressure and acceleration and moving just the required to complete the task. These savings permit performing repetitive tasks for a longer time and reducing the damage to articulations. Performing repetitive actions in a healthy way, without damage, have several productive consequences: taking a maximum advantage of the learning

**17**

institutions:

**Acknowledgements**

*Women, Ergonomics and Repetitiveness DOI: http://dx.doi.org/10.5772/intechopen.82065*

day and also within each week.

be done by gender-based and serial sampling.

human reliability and minimizing turnover.

social risks from which both genders can benefit.

in productivity.

these findings.

curve, with a better adaptation to muscular/cognitive level and with notable effects

There is another implication of the findings, which is related to the validity of sampling in risk assessment. OCRA has proven to be a valid and reliable method for assessing the risk of repetitive tasks; however, one cannot speak of an index of risk associated with the task of, for example, packaging. Each worker has a different rhythm, so the frequency multiplier changes. But it not only changes from worker to worker but also changes the factor at the beginning of the day than at the end of the

Another disruptive factor is the strength, acceleration, and the way the movements are made. OCRA considers technical actions, but this can be done by mobilizing different muscle groups, with significant variations of strength, acceleration (force is related to mass and acceleration), and associated fatigue. Therefore, repetitive work evaluations, especially when establishing work-gender relations, should

One of the most interesting results in this research is related to the different ways men and women face repetitive work. It is clear that women could maintain constant work rhythms, due to better energy management in terms of strength and ranges of movement. However, the group of men showed consistent behavior when starting cycles with greater force but applying less force throughout the day and the week. The range of motion in the male group behaved inversely proportional to that of the applied force, showing ranges of motion and activation of a greater number of muscle groups as the force diminished, in the time. Biomechanically, this situation can be explained as a physical compensation, which uses more muscle groups than necessary to assist fatigued groups. It is not clear why this happens. The answer seems to be not related to the biomechanical sphere, but to a series of conditioning factors of human behavior, determined by psychological, social, and cultural issues. It was not within the scope of this research to deepen the identification of these conditions, but it seems a very promising line of research that can be derived from

What seems to be clear is that it is not due to special anatomical conditions, although the development of "muscle intelligence" may be linked to a mechanism of evolutionary adaptation, since historically the woman has been performing tasks more repetitive than the man attending to the theory of the cultural division of labor [31]. This adaptation could also intervene in the mental sphere. Thus, from a macroergonomic point of view, the female population was more resilient: able to sustain the work rhythms over time, which allows increasing labor availability and

Then, a fair comparison of the conditions in which men and women work is inconsistent, since although they are interacting with the same objects, means, and conditions of work, the way each gender work is different, and it conditions that productive systems self-segregates naturally, establishing jobs typically "feminized" based on the best adaptation of women to low-load repetitive work, so this segregation seems to be justified for productive reasons, and not cultural in all cases.

However, if these protective factors are identified, it can be incorporated into the working procedures as part of an action plan to prevent the ergonomic and psycho-

Author wants to thank the collaboration for this chapter to the following

#### *Women, Ergonomics and Repetitiveness DOI: http://dx.doi.org/10.5772/intechopen.82065*

*Safety and Health for Workers - Research and Practical Perspective*

absence, rest, and labor rotation.

**4. Conclusions and final ideas**

on a differents patterns but complementaries.

for longer time in the repetitive job workplaces.

and postoperative disability than men.

that "female gender was a significant predictor of tendinitis."

that minimize the effects of repetitive work in women.

A more longitudinal analysis of the marginal productivity per worker in the last year shows even more definitive results, with the female sample having an annualized productivity 18.3% higher than the male sample, considering the effect of

The comparison between men and women in labor terms is not fair. Both genders perform different tasks, with different expositions, different patterns of rotation, and different resources to face the work. Probably, both gender are based

Several studies show a major biomechanical affectation in female group than male group of workers in a great variety of industrial tasks [26]. But at least performing repetitive tasks involving a prehensile effort of less than 15 N or manual loads of less than 50 Gr per repetition, these results are not caused by a gender weakness but a higher-risk exposition in both ways: in short-term time, because women perform more repetitions monthly than men; and in long-term time, because they can support repetitive loads of work for longer time, so they remain

These results are consistent with Tomaskovic-Devey [27], which results show that exposure to repetitive work is more frequent among working women; and it is consistent with Kilbom [28], whose results show that a greater proportion of women than men suffer problems especially in the upper limbs; finding out that occupations at high risk of musculoskeletal problems in upper limbs, the majority had a mostly female workforce. Results are consistent with NIOSH too, showing

Although the incidence and prevalence for some authors have not yet been established for De Quervain's disease, some report prevalence between 2.5 and 8% in women of the total working population. Women are more frequently affected than men (8:1 ratio), and the age of onset is between 30 and 60 years [29].

Hobby [30] tested the effects of age and gender on the results of surgery for carpal tunnel release in 97 patients with a diagnosis of CTS. Evaluation was performed before the release and 6 months after surgery. Women reported more symptoms

These researches show that repetitive work is more frequent among feminized positions, and musculoskeletal disorders in upper limbs are more frequent, pointing to an obvious correlation. But these studies do not inquire about the technical justifications for these phenomena and only describe them. This chapter is not intended to delve into the results of prehensile strength, acceleration of movements, or comparative productivity between genders (which are found in more detail in another article by the authors [25]) but to express conclusions that may be useful to understand probable causes of the phenomena studied and thus explore measures

This study does not show a greater biomechanical resistance of the feminine articular systems in relation to the masculine ones, but it shows a greater "muscular intelligence" in the accomplishment of the repetitive tasks, which acts as a protective factor and enhances productivity. This feature is based on energy savings and biomechanical resources in each technical action, applying the pressure and acceleration and moving just the required to complete the task. These savings permit performing repetitive tasks for a longer time and reducing the damage to articulations. Performing repetitive actions in a healthy way, without damage, have several productive consequences: taking a maximum advantage of the learning

**16**

curve, with a better adaptation to muscular/cognitive level and with notable effects in productivity.

There is another implication of the findings, which is related to the validity of sampling in risk assessment. OCRA has proven to be a valid and reliable method for assessing the risk of repetitive tasks; however, one cannot speak of an index of risk associated with the task of, for example, packaging. Each worker has a different rhythm, so the frequency multiplier changes. But it not only changes from worker to worker but also changes the factor at the beginning of the day than at the end of the day and also within each week.

Another disruptive factor is the strength, acceleration, and the way the movements are made. OCRA considers technical actions, but this can be done by mobilizing different muscle groups, with significant variations of strength, acceleration (force is related to mass and acceleration), and associated fatigue. Therefore, repetitive work evaluations, especially when establishing work-gender relations, should be done by gender-based and serial sampling.

One of the most interesting results in this research is related to the different ways men and women face repetitive work. It is clear that women could maintain constant work rhythms, due to better energy management in terms of strength and ranges of movement. However, the group of men showed consistent behavior when starting cycles with greater force but applying less force throughout the day and the week. The range of motion in the male group behaved inversely proportional to that of the applied force, showing ranges of motion and activation of a greater number of muscle groups as the force diminished, in the time. Biomechanically, this situation can be explained as a physical compensation, which uses more muscle groups than necessary to assist fatigued groups. It is not clear why this happens. The answer seems to be not related to the biomechanical sphere, but to a series of conditioning factors of human behavior, determined by psychological, social, and cultural issues. It was not within the scope of this research to deepen the identification of these conditions, but it seems a very promising line of research that can be derived from these findings.

What seems to be clear is that it is not due to special anatomical conditions, although the development of "muscle intelligence" may be linked to a mechanism of evolutionary adaptation, since historically the woman has been performing tasks more repetitive than the man attending to the theory of the cultural division of labor [31]. This adaptation could also intervene in the mental sphere. Thus, from a macroergonomic point of view, the female population was more resilient: able to sustain the work rhythms over time, which allows increasing labor availability and human reliability and minimizing turnover.

Then, a fair comparison of the conditions in which men and women work is inconsistent, since although they are interacting with the same objects, means, and conditions of work, the way each gender work is different, and it conditions that productive systems self-segregates naturally, establishing jobs typically "feminized" based on the best adaptation of women to low-load repetitive work, so this segregation seems to be justified for productive reasons, and not cultural in all cases.

However, if these protective factors are identified, it can be incorporated into the working procedures as part of an action plan to prevent the ergonomic and psychosocial risks from which both genders can benefit.

#### **Acknowledgements**

Author wants to thank the collaboration for this chapter to the following institutions:

