Comparison Between Measured and Proposed Back Length Distances for Pattern Block Construction

The aim of this study was to compare the back length distances (BacLen) from contemporary construction systems with the measured back length distances of the Slovenian young female population to establish which back length presented in diff erent contemporary construction systems fi ts best to the body dimension of a specifi c target market group. 160 female students (aged between 19 and 27 years) from the University of Ljubljana (Slovenia) volunteered for the study. The results showed that the measured back length distances diff ered signifi cantly from those obtained from the tables of contemporary construction systems or calculated as a secondary measure according to these systems. The measured BacLen distances were the same in all size groups and did not increase as did with all analyzed contemporary construction systems. The range of measured BacLen distances inside each size group was substantial (33−43 cm) and the measured BacLen distances were not in correlation with the body height, bust girth and in consequence nor with the calculated BacLen distances. In conclusion, the values for back length distances as proposed by diff erent contemporary construction systems diff er signifi cantly from the measured ones in the young Slovenian female population. We thus suggest including back length distance as a directly measured parameter for a pattern block construction when producing made-to-measure clothes.


Introduction
Dresses represent an indispensable piece of apparel in every woman's wardrobe.Because the expectations of today's customers are increasing steadily and are accompanied by an excessive o er of dresses by di erent producers and retailers, the proper size and t of the clothes is important since it in uences the buying decision of the customers [1].e t of the clothes is closely linked with the body dimensions incorporated in the basic pattern blocks of clothes, while every production of garments requires the development of corresponding patterns.Usually measurement tables and basic block patterns in industry are already established and xed, but they are not necessarily the best re ection of the body dimensions of their target market groups [2,3].Back length (BacLen) distance is needed in developing the basic dress pattern block and play an important role in creating the proper t of the dress on the level of the natural waist girth.If it is shorter from the real one, the dress will be too loose under the natural waist level, if it is longer, the close tted dress will strand on the hips and cause the balloon of excessive material above the natural waist level.Higher is the di erence between the real value of the back length distance and the one incorporated in the basic block pattern of the dress, more distinctive this deviation would be.In uence of the back length on the t of the dress on the body is o en overlooked by contemporary construction systems.In practice, back length distance is usually de ned as a secondary measure which can be calculated with an equation from one of the primary measure.Within German Müller system there are two equations proposed based on body height (see equations 1 and 2 in the Methods) [4−7].In Hungarian so called decimal system [8] they calculate it from the armscye depth, body height and bust girth (see equations 3 in the Methods).Beside this, most of the contemporary construction system includes it in their measurement tables.Values in those tables slightly di erentiate from one system to another and increase with the change of the bust girth [5, 6, 9−11].Di erences of BacLen distances from di erent construction systems set with measurement tables or with equations pose a question, which distance ts best to the natural shapes of di erent target groups of female bodies.One way to get the answer is to compare these distances with those from the real subjects.ere is no common agreement how to measure BacLen distance, while construction systems o er di erent measurement methodologies [5,6,9,10,12,13].It seems that the most consistent way to select the proper methodology is to follow the nature of dress basic pattern block development.In most of the pattern construction systems, the Ba-cLen distance is applied in the basic pattern block as a vertical distance from the 7th cervical bone to the natural waist line in the middle back of the body [5−7, 9, 11, 14].e methodology of measurement BacLen distance in the present study was performed in that way.
e aim of this study was to compare BacLen distances from contemporary construction systems with the measured distances of the Slovenian young female population to establish which BacLen distance presented in di erent contemporary construction systems ts the best to the body dimension of that speci c market target group.

Participants
e anthropometric surveys was carried out on 160 female students (age 19−27 years) from the University of Ljubljana (Slovenia) who volunteered in the study.Subjects were selected to t into a single body height group as suggested in SIST EN 13402-3 [15] (164−172 cm).A division was made according to their bust girth measure, since it is the most important measure in the basic pattern developing of a dress.Five major groups were formed according to SIST EN 13402-3 [15].All participants were well informed about the procedures of the experiment.None of them gave birth.

BacLen distances from the measurement tables
e BacLen distances were obtained from the measurement tables of the following contemporary construction systems: Müller's system [4−6] is presented with two measurement tables (Müller1 and Müller2), Aldrich's system [9], Mors de Castro's system (MdC) [10] and Jansen system [11].In the study only the values of those systems which followed the same measurement methodology for Bac-Len distances as the one performed in the study were chosen.e values obtained from the tables Distances for Pattern Block Construction Tekstilec, 2014, letn.57(3), str.212-219 were valid for the female population between 164 and 172 cm body height (here reported as 168 cm) and for selected size groups based on bust girth.

Calculated BacLen distances
e rst calculated BacLen distance was based on rst Müller's system equation [4−6]: where BH stands for body height.
e second calculated BacLen distance was calculated according to the second Müller's system equation (Equation 2) [4−6]: where BH stands for body height.
e third calculated BacLen distance was calculated according to the equation 3 based on a decimal base pattern design for women's clothes [8]: where armscye is given in equation 4: e bust girths and body height of the subjects were measured according to the procedures described in the anthropometric survey.

Anthropometric survey
During the measurement, the participants were standing on the levelled ground in their natural posture with the feet together and with center of gravity distributed equally on both legs.eir heads were aligned with the Frankfurt's line.During the measurement, they breathed normally with abdomen relaxed with arms hanging down freely along the torso or slightly li ed up but in the way that their posture or body dimensions under consideration did not change.Participants were dressed in underwear and barefoot.Survey was performed in forenoon by the same person and an assistant who recorded the data.
e values were always repeated before they were put into the anthropometric form and were round up to a higher value with 0.5 cm accuracy.First, the anthropometric point of the 7 th cervical bone was marked with the anthropometric pencil.e point was better determined when the person bent her head forward and the 7 th cervical bone exposed more clearly.Following its position, the person returned to her natural posture with her head aligned with the Frankfurt's line, when the anthropometric point of the 7 th cervical bone was marked.e plane of natural waist level was selected and marked with 3mm wide elastic band (upper band), which did not compress the so tissue and therefore a ected the values of measurement.e natural waist level was marked between the top of the hip bones and the lower ribs where the girth is the smallest according to ISO 8559 [12] and ISO 3635 [16] (Figure 1).e band was adjusted around the body in a way that the ellipsoid levels of the natural waist girth were perpendicular to the longitudinal axis of the body.Measured back length distance (BacLen_m) was taken as the distance measured from the marked anthropometric point of the 7th cervical bone to the upper edge of the string on the marked waist line (Figure 1, le ).
e bust girth was measured with dimensionally stable tape-measure as the maximum horizontal girth during normal breathing with the subject standing in her natural posture and tape-measure passed across the nipples but adjusted around the body in a way that the ellipsoid level of the bust girth were perpendicular to the longitudinal axis of the body (Figure 1, right).
e measurements of body height (BH) were performed with anthropometer as the vertical distance between the crown of the head and the ground, with the subject standing in their natural posture with the feet together.

Statistics
e participants with the body height 168 cm (164− 172 cm) were arranged into size groups according to their bust girth in the range of 4 cm as it is suggested in SIST EN 13402-3 [15].Five size groups were formed with the bust girths 80 cm (78.5−82 cm), 84 cm (82.5−86 cm), 88 cm (86.5 to 90 cm), 92 cm (90.5−94 cm) and 96 cm (94.5−98 cm).For each group, basic statistical parameters of analyzed variables were calculated.Statistical signicances of di erences among the groups were rst tested with ANOVA and then with post-hock Ttests for single pairs of groups (Bonferroni correction).Statistical signi cances of di erences among di erent BacLen distances (measured and calculated) inside the single size group were tested rst with ANOVA and then with post-hock T-tests for single pairs of variables (Bonferroni correction).Pearson correlation coe cients were calculated between measured and calculated BacLens and obtained anthropometrical measurements.Results were statistically processed with the SPSS (version 22, IBM SPSS, New York, USA).Alpha error was set to 5% (two-tailed).

Results
Back length distances obtained from di erent tables of included contemporary construction systems are presented in Table 1.Among the systems, Aldrich system gives the lowest values for smaller size groups while Müller1 gives the lowest values for bigger size groups.Müller2 system provides the greatest values for all size groups.However, the di erences among systems are small (less than 1.2 cm).e smallest BacLen distance is 40.2 cm in Aldrich system for women with bust girth 80 cm and the largest 42.0 cm in Müller2 and Mors de Castro's system (MdC) for the women of bust girth 96 cm.Inside the single construction systems, the di erences among size groups are again rather small (0.4−1.6 cm).Table 2 shows that the mean body heights of participants from analyzed size groups did not di er statistically signi cantly (p = 0.650) among the size groups what consequently lead to non-signi cant di erences (p < 0.650) in calculated BacLen distances from the body height (BacLen_4 and BacLen_4_1) among the groups.In BacLen_DPD, which calculation was based on the bust girth as well as on the body height, the mean di erences among size groups were statistically signi cant (p < 0.001).e mean BacLen_DPD distances were in a range 41.4−42.4cm.Although the di erences among groups were statistically signi cant, they were small in the absolute values up to 1.0 cm).Di erences between BacLen_4 and BacLen_4_1 were xed according to the formulas 1 and 2 to 1 cm for each size group.Di erences between the BacLen_4 and BacLen_DPD 0.5 cm or less, and between BacLen_4_1 and BacLen_DPD less than 1.3 cm.Results of the BacLen distance as measured in the present study are presented in the Table 3. e largest di erence between mean size group values was 0.5 cm. e distances were not aligned according to the size groups nor were di erences among groups statistically signi cant (p > 0.05).However, the variability inside size groups was much larger, since standard deviations in size groups were greater than 2 cm, except in the size group 84 cm. e ranges between the smallest and greatest BacLen distance in size groups were 7−9.5 cm.Standard deviations of measured BacLen was approximately 4 times greater than in calculated BacLens.
e di erence between calculated BacLen (Table 1) and measured BacLen values (Table 3) are presented in Table 4. e most striking observations were substantial di erences regarding BacLen values from the construction systems and the size groups measured.BacLen di erences increased as the bust girth increased.e measured BacLen distance was shorter in all cases.e largest di erence excided 3 cm, most of them were more than 2 cm which is more than the di erences among the size groups inside the systems.e di erences between calculated and measured Ba-cLen are presented in Figure 2. Comparison of the di erences between mean measured BacLen distance and mean distances of BacLen_4, BacLen_4_1 and BacLen_DPD showed that the di erences were statistically signi cant in all size groups between all analyzed pairs of variables (Figure 2).Measured BacLen was systematically smaller than calculated BacLen in all size groups.e mean di erences between BacLen_m and calculated BacLens were from 1.5 cm  Table 5 shows that BacLen_m was not statistically signi cantly related to any of calculated BacLens (p > 0.05).Pearson correlation coe cients between pairs of calculated BacLen were highly signi cant (p < 0.001).
As an example, di erently obtained BacLen distances were put into the shape of the basic dress pattern for a single size number to present obtained di erences graphically (Figure 3).e di erences resulting from di erent BacLen distances a ected the shapes of curved lines of the side seams in the level of the natural waist lines and consequently the t of the dress on mentioned body level.

Discussion
e main ndings of this study were that (i) measured back length distances di ered signi cantly from those obtained from the tables of the contemporary construction systems or calculated as a secondary measure according to these systems, (ii) measured BacLen distances were the same in all size groups and did not increase as the size group increased like with all analyzed contemporary construction systems (iii) the range of measured BacLen distances inside each size group was substantial (33−43 cm), and (iv) the measured BacLen distances were not correlated with body height or bust girt and therefore also not to calculated Bac-Len distances.
e di erences in BacLen distances among the analyzed systems as well as among the size groups inside those systems were rather small, mostly less than 1 cm and the BacLen distances increased as the size group increased.It seems that di erent contemporary constructing systems follow similar approach in setting their BacLen distances.In contrast to them, the measured BacLen did not follow any trend and its mean distances did not signicantly di er among the size groups nor they show  3).e range inside the size groups in measured BacLen values were much larger, from 7 cm in the group with 84 cm bust girth up to 9.5 cm in the groups with 80 and 96 cm bust girth than in measurement tables which raises a question of introducing the sub-sizes upon BacLen values.Calculated BacLen distances should better t to individual characteristics of the subjects since they are based on their known dimensions, e.g.body height or bust girth.However, in the present study measured BacLen and calculated BacLens were not correlated.Additionally, the mean di erences between calculated BacLens and measured BacLen were signi cant and large enough to a ect the t of the clothes. is means that the calculated Bac-Lens did not re ect the actual body dimension of young Slovenian females.Di erences in BacLen distance will a ect the shape of the basic dress block around the natural waist level as presented in Figure 3. e BacLen distance is not only important in the process of developing basic dress pattern blocks in the sense of proper t.It is also important for every garment that covers the part of the body over the natural waist level like blouses, t-shirts, coats, overalls etc. Smaller is the ease of the clothes incorporated in the basic pattern cut (in other words, the tter the clothes are), the more important becomes the right value of Bac-Len distance.e importance of selecting the real values of Bac-Len distance is even more important in the madeto-measure business.Values of BacLen distances of the participants in the survey vary 33−44 cm, which mean 11 cm di erences in between.If we for example developed the basic dress pattern block for women with much smaller value of Bac-Len distance, ignoring this data and using the one from the measurement tables or calculated one, the dress would strand on the hips and cause the balloon of excessive material above the natural waist level.Alterations would not be possible because of the lack of the textile material on the side seam above the waist level.is problem would be smaller if the real value of BacLen distance is larger from the one incorporated in the basic block pattern since it would cause only very poor t of the garment.Alterations would still be possible and necessary.Anyways time and energy put in those alterations means lost money and raising the prices of the product, which cannot help businesses to maintain competitive advantage on the market.is is another reason to include BacLen distance into the anthropometric surveys as one of the important measures that in uence the shape of the pattern cut and consequently the t of the clothes.In the past, there was a tendency towards reducing the numbers of primary measures, because manual anthropometric surveys are time consuming and costly.However, in the last decade, with the use of 3D body scanners, this is changing dramatically.Today the information about body dimensions can be obtained faster and more users friendly.
is gives possibility to obtain signi cantly more measures directly from the bodies, among which back length distance should be included [17,18].Additionally, large data bases of clothing 'customers' can be created and clothing companies would have possibilities to extract from databases only those 'customers' important for their business.In that way the information of their real values would give them competitive advantage on the market and in the same time give consumers better satisfaction in a sense of proper t of the garments on their bodies.

Conclusions
In conclusion, the values for back length distances as proposed by di erent contemporary construction systems di er signi cantly from the ones measured in young Slovenian female population.e main di erences were observed in obtained range of measured BacLen distances in comparison to other systems and no relationship between measured and calculated BacLens.It is suggested to include back length distance as a directly measured parameter for pattern block construction when producing madeto-measure clothes.

Figure 1 .
Figure 1.Measurement of the back length (le ) and bust girth (right)

Table 1 .
Back length values obtained from di erent measurement tables of women with di erent bust girth Legend: Max-min -di erence between maximal and minimal bust girth.

Table 4 .
Mean di erences between BacLen_measured and other BacLen distances (Based on Table1)